MINI-OX

Mechanistic Aspects of Activation and Preparative Applications of Organic Peroxides and Molecular Oxygen in Regio- and Stereoselective Synthesis


Highlights - Methods - Selected Publications

Research Activities:

The research interest in this area concern oxygen, sulfur and nitrogen transfer through oxidation processes of organic and metallorganic compounds, of which oxyfunctionalizations constitute the major effort. For this purpose, molecular oxygen and hydrogen peroxide with its derivatives (hydroperoxides, perhydrates, peroxy acids, acyl peroxides, dioxiranes, dioxetanes, etc.) are used directly or are being activated chemically and/or photochemically to perform chemo-, regio- and stereoselective stoichiometric oxidations (catalytic ones are the subject of MINI-CAT). Selectivity, particularly diastereoselectivity, is achieved through the synergism of electronic, steric and stereoelectronic effects with conformational control (allylic, geminal and peri strain). The purpose of this work is to understand the mechanisms of oxidation processes in an effort to design more selective, efficient and convenient transformations for preparative purposes.

Oxyfunctionalizations with molecular oxygen deal mainly with photooxygenations, in which singlet oxygen is produced either through photosensitization or chemical reactions (arene endoperoxides, transition-metal peroxo complexes, etc.) to perform selective oxidations ([4+2] and [2+2] cycloaddition, ene reactions, hetero-atom oxidations). Of these transformations with singlet oxygen, the synthetically most valuable is the ene reaction (Schenk reaction), which has received our most concentrated attention. In this way, valuable and time-saving syntheses of optically active building blocks and natural products have been developed from simple electron-rich and electron-poor olefins. Stereocontrol (erythro or threo) is achieved through a perepoxide-like transition-state structure in the ene reaction, in which p-facial preference is dictated in electron-rich olefins by conformational alignment through 1,3-allylic strain and attractive interactions through hydrogen bonding (threo control) or electrostatic and steric repulsions (erythro control); stereoelectronic factors (Houk model) operate for eletron-poor substrates, which override hydrogen-bonding effects to provide threo selectivity. It is all a question of whether exiplex formation between singlet oxygen and the olefinic substrate is rate-determining or not (Display A).

Enantioselectivity is achieved through the use of appropriate chiral auxiliaries (Porter-Kanemasa, Evans, etc.), for which steric factors are decisive. Most recent efforts attempt to generate "chiral" singlet oxygen through the thermal retro-cleavage of optically active arene endoperoxides to perform asymmetric oxyfunctionalizations directly.

In the chemical activation of hydrogen peroxide (catalytic transition-metal-activated processes are the subject of MINI-CAT) for selective oxyfunctionalizations most of our efforts concern dioxiranes, but perhydrates and peroxy acids also receive attention. Dioxiranes are conveniently prepared from ketones by treatment with Caroate and isolated as ketone solutions by distillation [cf. publication No. 373 for the preparation of dimethyldioxirane (DMD)]. When the substrate and oxidized product tolerates aqueous conditions, the in-situ procedure is preferred (cf. publication No. 347). A large variety of electron-rich and electron-poor substrates may be oxyfunctionalized by DMD, which includes epoxidations (p bonds), hydroxylations (s bonds) and hetero-atom oxidations (lone pairs), of which representative examples are given in Display B. Unquestionably, dioxiranes are valuable oxidants in organic synthesis.

Most recently also enantioselective oxidations, especially epoxidations, have been achieved through the use of optically active ketones from the sugar and TADDOL ex-chiral pool or of the binaphthol type. C2 symmetry provides particularly effective steric control in the attack of the chiral dioxirane upon the prochiral substrate. The concerted mechanism of oxygen-atom transfer applies, the favored (by ca. 7 kcal/mol) transition-state geometry entails the spiro "butterfly" arrangement rather than the planar one (Display C).

Sulfur-atom transfer directly to olefins constitutes a recent pursuit in our intentions to develop selective reactions. These efforts have been kindled by our discovery that certain thioozonides episulfidize diastereoselectively strained olefins (norbornene, trans-cyclooctene, etc.) to afford in good yields the corresponding thiiranes. A more convenient direct episulfidation route entails photochemical activation of sulfines (thione oxides) in the presence of strained olefins, in which sulfur-atom transfer in up to 90% yields have been achieved. Presumably, in-situ-generated oxathiiranes are the active sulfur-atom-transferring species. However, on thermal activation, the sulfines episulfidize trans-cyclooctene through the intermediary sultenes, formed by 1,3-dipolar addition of the sulfines to the olefin. The episulfidation chemistry is shown in Display D.

Most recent efforts deal with the challenging prospects of the nitrogenation of organic compounds. In view of the mechanistic kinship of triazoline-3,5-diones (TAD's) in their enophilic reactivity to singlet oxygen (both engage three-membered-ring dipolar intermediates, perepoxide-like for 1O2 and the aziridinium-imine-like for TAD's), the ene reaction is exploited to introduce the nitrogen functionality. The use of chiral auxiliaries (Porter-Kanemasa, Evans, etc.) allows asymmetric azetation through steric control (Display E). The resulting urazoles are subsequently transformed into amino groups through reduction methods. Since this has been traditionally a difficult problem, new methods have been searched for to release the amino functionality from the urazole.

 

Most recently, nitrosoarenes (ArNO) have been employed to introduce nitrogen functionalities into olefins through the ene reaction.

Research Activities - Methods - Publications

Highlights:

Excellent threo selectivity (d.r. > 90:10) was achieved in the 1O2 ene reaction of chiral, electron-rich alcohols with 1,3-allylic strain, in which hydrogen bonding by the allylic hydroxy functionality directs p-facial control, rationalized in terms of the perepoxide-like structured exciplex 1.

While chiral allylic amines, like above, display high threo selectivity (d.r. > 95:5), their di-Boc derivatives show high erythro preference (d.r. > 95:5) through steric and electrostatic p-facial differentiation (cf. transition state structure 2); this valuable synthetic methodology was utilized in an efficient synthesis of the optically active natural product merucathin (3).

Chiral electron-poor olefins with 1,3-allylic strain also undergo a threo-selective ene reaction with 1O2, but Houk's stereoelectronic effect applies (cf. transition-state geometry 4) rather than hydrogen bonding (when X = H); this stereocontrol was employed in the to date most efficient asymmetric synthesis of mahuba lactone (5).

The ene reaction of triazoline-3,5-diones and tiglic amides 6 with Porter-Kanemasa chiral auxiliaries has been shown to proceed in perfect diastereoselectivity to provide, after hydrolysis of the oxazolidine moiety, nitrogen-functionalized products in high optical purity. For the first time, opposite diastereoselectivities have been observed for mCPBA (like due to hydrogen bonding) versus dimethyldioxirane (unlike due to steric effects).

The [4+2] cycloaddition of 1O2, the smallest possible dienophile, to sorbic amides 7 with Porter-Kanemasa chiral auxiliaries proceeds completely diastereoselecitivity to afford, after reductive cleavage of the peroxide bond, oxyfuntionalized products in high optical purity.

Application of our stereochemical probe 8 to the epoxidation by perhydrates allowed to assess that the transition-state geometry (cf. structure 9) in this oxygen transfer is analogous to that of peroxy acids (high threo selectivity).

The corresponding dioxirane of the TADDOL-derived C2-symmetric ketone 10 was shown to be an effective enantioselective epoxidant of prochiral olefins and hydroxylating agent of prochiral enol ethers with ee values up to 90%.

By means of the cyclopropylcarbinyl radical clock and complete diastereoselective epoxidation of trans-cyclooctene it was unequivocally established that these oxygen transfers are concerted rather than radical type processes; the spiro-structured "butterfly" transition state 11 applies.

The perfect (100%) retention of configuration in the hydroxylation of S(+)-2-phenylbutane proves that this CH insertion proceeds through the concerted transition state 12 instead of radicals (oxygen-rebound mechanism).

A new oxidative method for the direct transformation of nitroarenes to phenols has been developed by first generating the Meisenheimer adduct through the addition of carbanions to the nitroarene and subsequent treatment with dimethyldioxirane; in the latter oxidation the phenol yield is improved significantly by trace amounts of water.

Optically active dioxiranes, generated in situ from the fructose-derived ketone 13, have been employed for the enantioselective desymmetrization of meso and d,l diols and their cyclic acetal derivatives into optically active a-hydroxy ketones.

By means of high-level computational methods, the threo selectivity due to hydrogen bonding between the hydroxy group of the allylic alcohol 14 (stereochemical probe, competition between 1,3- and 1,2-allylic strain) and the peracid has been rationalized mechanistically.

The thioozonide 14, readily available by photooxygenation of the corresponding thiophene through [4+2] cycloaddition, is the first efficient sulfur-transfer agent for the direct episulfidation of strained alkenes (e.g. trans-cyclooctene, norbornene). Oxathiiranes have been postulated as the active sulfur-functionalizing species in this stereoselective process (complete retention of the olefin configuration).

Oxathiiranes 15, generated in situ through the known photochemical cyclization of sulfines, have been used for the efficient direct episulfidation of strained alkenes, a process of considerable preparative value.

Thermally persistent sultenes 16 have been prepared by the 1,3-dipolar cycloaddition of sulfines to trans-cyclooctene and shown to serve as effective episulfidation agents under acid catalysis.

Research Activities - Highlights - Methods - Selected Publications

Methods:

Photooxygenation; product studies; stereolabeling; trapping and radical-clock experiments; kinetics: X-ray structure determinations; 600-MHz NMR spectroscopy; optical resolution.

Research Activities - Highlights - Methods - SelectedPublications

Research Activities - Highlights

Selected Publications:

Dissertations:

106. S.G. Bosio, "Typselektivitåt und Diastereoselektivitåt in den Oxidationen von chiralen oxazolidinonsubstituierten Encarbamaten mit Singulettsauerstoff, Dimethyldioxiran und meta- Chlorobenzoesåure", March 2003.

105. R. Bargon "Molybdänkatalysierte Schwefeltransfer-Reaktionen auf Isonitrile, Alkene und Allene", December 2002.

103. O. Krebs "En-Reaktion von Nitrosoaren, Triazolindion und Singulettsauerstoff: Mechanismus und Anwendung in der stereoselektiven Synthese", September 2002.

101. G. Degen "Asymmetrische Weitz-Scheffer-Epoxidierung mit optisch aktiven Hydroperoxiden oder Phasentransferkatalysatoren", March 2002.

98. B. Fröhling "Reaktionen elektrophiler und nucleophiler Schwefeldonoren mit cyclischen Alkenen und Alkinen", March 2002.

95. K. Schmid "Synthese von optisch aktiven Tetrahydrofuranen und 4,6-Didesoxyfuranosen", June 2001.

94. S. Schambony "Chirale Oxazolidinauxiliare zur Kontrolle von Diastereo- und Regioselektivität in der En-Reaktion von Singulettsauerstoff“, March 2001.

93. N. Bottke "Regioselektive- und diastereoselektive Aminofunktionalisierung von trisubstituierten Alkenen mit Nitrosoverbindungen: Mechanismus der Nitroso-En-Reaktion“, March 2001

85. C.-G. Zhao "Chapter 1: Asymmetric Epoxidation and C-H Oxidation by Optically Active Dioxiranes; Chapter 2: Dimethyldioxirane (DMD) Oxidation of s H Adducts of Nitroarenes and of Nitronates", December 1999.

78. S. Weinkötz "Thiophenendoperoxide und Thiocarbonyl-S-oxide als Schwefeldonoren für die direkte und stereoselektive Episulfidierung cyclischer Alkene", March 1998.

79. T. Wirth "Untersuchungen zur Nutzung von Singulettsauerstoff als selektives Oxidans in der enantioselektiven Synthese: Diastereoselektive Photooxygenierungen von chiralen elektronenarmen Alkenen und Dienen", March 1998.

68. D. Golsch "Selektive Oxidation von Heteroatom-Systemen mit Dioxiranen, Persäuren und Übergangsmetallkatalysatoren", July 1996.

66. L. Blancafort "Mechanistische Studien zur Reaktivität von a-Peroxylactonen gegenüber Nucleophilen", July 1996.

65. A. Smerz "Diastereoselektivität der Epoxidierung mit Dioxiranen", July 1996.

58. M. Prein "Diastereoselektivität der [4+2]-Cycloaddition von Singulettsauerstoff", March 1995.

57. H.-G. Brünker "Regio- und diastereoselektive Singulettsauerstoff-En-Reaktion (Schenck-Reaktion) chiraler, in Allyl- und Homoallylstellung heteroatomsubstituierter, acyclischer Olefine; Vergleich mit diastereoselektiven Epoxidierungen, Anwendung der Reaktion in der Naturstoffsynthese", March 1995.

56. V. Nava Salgado "Stereoselektive Transformationen von a-Methylen-b-lactonen als maskierte Allene und Allenäquivalente", January 1995.

Papers:

948. Griesbeck, A. G.; Bartoschek, A.; Adam, W.; Bosio, S. G. "Photooxygenation of 1,3-Dienes". In Handbook of Organic Photochemistry and Photobiology, 2nd ed.; Horspool, W. M., Lenci, F. (Eds.); CRC Press, Inc.: London, 2003; Chapter 25, pp 25-1 to 25-19.

947. Griesbeck, A. G.; El-Idressy, T. T.; Adam, W.; Krebs, O. "Ene Reactions with Singlet Oxygen". In Handbook of Organic Photochemistry and Photobiology, 2nd ed.; Horspool, W. M.; Lenci, F.(Eds.); CRC Press, Inc.: London, 2003; Chapter 8, pp 8-1 to 8-2

946. Adam, W.; Gogonas, E. P.; Hadjiarapoglou, L. P. “A Facile Diastereoselctive Synthesis of Functionalized 1,2,3-Trisubstituted Benzocyclopentenes through the Cycloaddition of Bis(phenylsulfonyl)iodonium Ylides to Cyclic Alkenes”, J. Org. Chem. 2003, 68, 9155-9159.

945. Adam, W.; Krebs, O. "Progress in the Regioselective and Stereoselective Allylic Nitrogen Functionalization by the Nitroso Ene Reaction", Chem. Rev. 2003, 103, 4131-4146.

944. Adam, W.; Alsters, P. L.; Beck, A.; Neumann, R.; Saha- Möller, C. R.; Seebach, D.; Zhang, R. "Chiral Hydroperoxides as Oxygen Source in the Catalytic Asymmetric Epoxidation of Allylic Alcohols by Sandwich-Type Polyoxometalates: Control of Stereoselectivity through a Metal-Coordinated Template", J. Org. Chem. 2003, 68, 8222-8231.

943. Adam, W.; Bargon, R. M.; Mloston, G. " Episulfidation of trans-Cyclooctene by 1,2,4-Oxadithiolanes", Eur. J. Org. Chem. 2003, 4012-4015.

941. Adam, W.; Gogonas, E. P.; Hadjiarapoglou, L. P. "Alkenyl CH-Insertion of a beta-Disulfone Iodonium Ylide into Flavones", Tetrahedron 2003, 59, 7929-7934.

937. Griesbeck, A. G.; Adam, W.; Bartoschek, A.; El-Idreesy, T. T. "Photooxygenation of Allylic Alcohols: Kinetic Comparison of Unfunctionalized Alkenes with Prenol-Type Allylic Alcohols, Ethers and Acetates", Photochem. Photobiol. Sci. 2003, 2, 877- 881.

936. Adam, W.; Sajimon, M. C.; Trofimov, A. V. "Viscosity- Dependent Diastereoselectivity and Product Selectivity in the Photodenitrogenation of a Spirocyclopropyl-Substituted DBH-Type Azoalkane", Photochem. Photobiol. Sci. 2003, 2, 677-680.

935. Adam, W.; Gogonas, E. P.; Hadjiarapoglou L. P. "Bis(sulfonyl)methyl Insertion into Alkenyl versus Phenyl Carbon- Hydrogen Bonds in the Reaction of Bis(sulfonyl)iodonium Ylides with Highly Phenylated Ethylenes", Eur. J. Org. Chem. 2003, 1064-1068.

934. Adam, W.; Gogonas, E. P.; Hadjiarapoglou, L. P. "A Remarkable Cycloaddition of Bis(arylsulfonyl)iodonium Ylide with Norbornene Derivatives for the Direct Synthesis of Functionalized Indanes", Synlett. 2003, 1165-1169.

933. Adam, W.; Beck, A. K.; Pichota, A.; Saha-Möller, C. R.; Seebach, D.; Vogl, N.; Zhang, R. "Control of Enantioselectivity Through a Hydrogen-Bonded Template in the Vanadium(V)- Catalyzed Epoxidation of Allylic Alcohols by Optically Active Hydroperoxides ", Tetrahedron: Asymmetry 2003, 14, 1355-1361.

931. Adam, W.; Bosio, W.; Wolff, B. "Chiral-Auxiliary-Controlled Diastereoselectivity in the Epoxidation of Enecarbamates with DMD and mCPBA", Org. Lett. 2003, 5, 819-822.

930. Adam, W.; Alsters, P. L.; Neumann, R.; Saha-Möller, C. R.; Seebach, D.; Zhang. R. "Highly Efficient Catalytic Asymmetric Epoxidation of Allylic Alcohols by an Oxovanadium-Substituted Polyoxometalate with a Regenerative TADDOL-Derived Hydroperoxide", Org. Lett. 2003, 5, 725-728.

929. Adam, W.; Bargon, R. M.; Schenk, W. "Direct Episulfidation of Alkenes and Allenes with Elemental Sulfur and Thiiranes as Sulfur Sources, Catalyzed by Molybdenum Oxo Complexes", J. Am. Chem. Soc. 2003, 125, 3871-3876.

928. Adam, W.; Krebs, O.; Orfanopoulos, M.; Stratakis, M.; Vougioukalakis, G. C. "Intramolecular and Intermolecular Kinetic Isotope Effects (KIE) in the Nitrosoarene Ene Reaction: Experimental Evidence for Reversible Intermediate Formation", J. Org. Chem. 2003, 68, 2420-2425.

926. Adam, W.; Alsters, P.; Neumann, R.; Saha-Möller, C. R.; Sloboda-Rozner, D.; Zhang, R. "A Highly Chemoselective, Diastereoselective and Regioselective Epoxidation of Chiral Allylic Alcohols with Hydrogen Peroxide, Catalyzed by Sandwich-Type Polyoxometalates: Enhancement of Reactivity and Control of Selectivity by the Hydroxy Group through Metal-Alcoholate Bonding", J. Org. Chem. 2003, 68, 1721-1728.

923. Bach, R. D.; Dmitrenko, O.; Adam, W.; Schambony, S. "Relative Reactivity of Peracids versus Dioxiranes (DMDO and TFDO) in the Epoxidation of Alkenes. A Combined Experimental and Theoretical Analysis" J. Am. Chem. Soc. 2003, 125, 924-934.

921. Adam, W.; Zhang, A. "Highly ?-Facial Stereoselective Aldol Reaction of (S)-Proline-Derived Amide Enolate with Benzaldehydes", Eur. J. Org. Chem. 2003, 587-591.

918. Adam, W.; Zhao, C.-G.; Saha-Möller, C. R. "Dioxirane Epoxidation of Olefins", Org. React. 2002, 61, 219-516.

917. Adam, W.; Kiefer, W.; Schlücker, S.; Saha-Möller, C. R.; Kazakov, D. V.; Kazakov, V. P.; Latypova, R. R.; "Formation of Singlet Oxygen During the Decomposition of Dimethyldioxirane, Catalyzed by Anionic Nucleophiles" In Bioluminescence and Chemiluminescence: Progress and Current Applications, Proceedings of the 12th International Symposium on Bioluminescence & Chemiluminescence; Stanley, P. E., Kricka, L. J., Eds.; World Scientific Publishing, Singapore, 2002, pp. 129-132.

914. Stratakis, M., Nencka, R.; Rabalakos, C.; Adam, W.; Krebs, O. "Thionin-Sensitized Intrazeolite Photooxygenation of Trisubstituted Alkenes: Substituent Effects on the Regioselectivity As Probed Through Isotopic Labelling", J. Org. Chem. 2002, 67, 8758-8763.

913. Adam, W.; Bosio, S. G.; Turro, N. J. "Control of the Mode Selectivity (Ene Reaction versus [2+2] Cycloaddition) in the Photooxygenation of Ene Carbamates: Directing Effect of an Alkenylic Nitrogen Functionality", J. Am. Chem. Soc. 2002, 124, 14004- 14005.

912. Adam, W.; Alsters, P. L.; Neumann, R.; Saha- Möller, C. R.; Sloboda, D.; Zhang, R. "A New Highly Selective Method for the Catalytic Epoxidation of Chiral Allylic Alcohols by Sandwich-Type Polyoxometalates with Hydrogen Peroxide", Synlett 2002,
2011-2014.

911. Adam, W.; Bottke, N.; Krebs, O.; Lykakis, I.; Orfanopoulos, M.; Stratakis, M. "Ene Reaction of Singlet Oxygen, Triazolinedione and Nitrosoarene with Chiral Deuterium-Labelled Allylic Alcohols: The Interdependence of Diastereoselectivity and Regioselectivity Discloses Mechanistic Insights into the Hydroxy-Group Directivity",
J. Am. Chem. Soc. 2002, 124, 14403-14409.

910. Adam, W.; Krebs, O.; Orfanopoulos, M.; Stratakis, M. "Control of Regioselectivity by the lone Substituent through Steric and Electronic Effects in the Nitrosoarene Ene Reaction of Deuterium-Labeled Trisubstituted Alkenes", J. Org. Chem. 2002, 67, 8395-8399.

906. Adam, W.; Malisch, W.; Roschmann, K. J.; Saha- Möller, C. R.; Schenk, W. A. "Catalytic Oxidations by Peroxy, Peroxo and Oxo Metal Complexes: An Interdisciplinary Account with a Personal View" J. Orgmet. Chem. 2002, 661, 3-16.

905. Adam, W.; Bosio, S., G.; Degen, H.-G.; Krebs, O.; Schumacher, D.; Stalke, D. "A Comparative Study on the Diastereofacial Control in the [4+2] Cycloaddition of Sorbates and the Ene Reaction of Tiglates with Singlet Oxygen and PTAD by a Variety of Chiral Auxiliaries", Eur. J. Org. Chem. 2002, 3944-3953.

904. Adam, W.; Krebs, O.; Saha-Möller, C. R. "Efficient p-Facial Control in the Ene Reaction of Nitrosoarene, Triazolinedione and Singlet Oxygen with Tiglic Amides of the Bornane-Derived Sultam as Chiral Auxiliary: An Economical Synthesis of Enantiomerically Pure Nitrogen- and Oxygen-Functionalized Acrylic Acid Derivatives", J. Am. Chem. Soc. 2002, 124, 12938- 12939.

901. Adam, W.; Bargon, R. M.; Bosio, S. G.; Schenk, W. A.; Stalke, D. "The Direct Synthesis of Isothiocyanates from Isonitriles by Molybdenum- Catalyzed Sulfur Transfer with Elemental Sulfur", J. Org. Chem. 2002, 67, 7037-7041.

898. Kazakov, D. V.; Maistrenko, G. Y.; Polyakova, N. P.; Latypova, R. R.; Kazakov, V. P.; Adam, W.; Trofimov, A.; Zhao, C.-G.; Kiefer, W.; Schlücker, S. "On the Chemiluminescence in the Oxidation of the Tetravalent Uranium to the Uranyl Ion by Dimethyldioxirane", Luminescence 2002, 293-298.

896. Adam, W.; Bosio,S. G.; Gogonas, E. P.; Hadjiarapoglou; L. P. "A Stereoselective and Regioselective Synthesis of trans,trans-Configured 1, 2, 3-Trisubstituted Indanes: Cycloaddition of Alkenes with Iodonium Ylides of b-Disulfones" Synthesis 2002, 14, 2084-2090.

895. Adam, W.; Bosio, S.; Turro, N. J. "Highly Diastereoselective Dioxetane Formation in the Photooxygenation of Enecarbamates with an Oxazolidinone Chiral Auxiliary: Steric Control in the [2+2] Cycloaddition of Singlet Oxygen through Conformational Alignment", J. Am. Chem. Soc. 2002, 124, 8814-8815.

893. Adam, W.; Bosio, S.G.; Fröhling, B.; Stalke, D. "Unusual Sulfur Chemistry in the Thermal Reaction of Sultene and Thiophene-Endoperoxide Sulfur Donors with Cyclic Alkynes: Reversible Formation of a Persistent Thiirenium Ion and Trapping of a Thiirene by [4+2] Cycloaddition", J. Am. Chem. Soc. 2002, 124, 8316-8320.

889. Lévai, A.; Koèevar, M.; Tóth, G.; Simon, A.; Vranièar, L.; Adam, W. "Synthesis and Dimethyldioxirane Oxidation of Tetrahydrobenzofurans", Eur. J. Org. Chem. 2002, 1830-1833.

884. Adam, W.; Kilic, H.; Saha-Möller, C. R. "An Efficient Regioselective and Diastereoselective Synthesis of the Epoxy-Quinol Functionality as Building Block for the Manumycin Antibiotics by the Sequence of Photooxygenation, Reduction and Weitz-Scheffer Epoxidation", Synlett 2002, 510-512.

883. Adam, W.; Cakmak, O.; Saha-Möller, C. R.; Tutar, A. "Highly Brominated Norbornanes by Photobromination as Precursors for the Convenient Synthesis of 2,3,5,6-Tetrabromo- and 2,3,5,6- Tetramethoxy-Substituted Norbornadienes", Synlett 2002, 49-52.

882. Cui, M.; Adam, W.; Shen, J. H.; Luo, X. M.; Tan, X. J.; Chen, K. X; Ji, R. Y.; Jiang, H. L. "A Density- Functional Study of the Mechanism for the Diastereoselective Epoxidation of Chiral Allylic Alcohols by the Titanium Peroxy Complexes", J. Org. Chem. 2002, 67, 1427-1435.

881. Voigt, B.; Porzel, A.; Adam, G.; Golsch, D.; Adam, W.; Wagner, C.; Merzweiler, K. "Synthesis of 2,24- Diepicastasterone and 3,24-Diepicastasterone as Potential Brassinosteroid Metabolites of the Cockroach Periplaneta Americana" Collect. Czech. Chem. Commun. 2002, 67, 91-102.

880. Adam, W.; Fröhling, B. "Lewis-Acid-Catalyzed Sulfur Transfer from a Sultene to Strained Alkenes" Org. Lett. 2002, 4, 599-602.

876. Adam, W.; Herold, M.; Hill, C. L.; Saha-Möller, C. R. "Allylic CH Oxidation versus Epoxidation of 2- Cyclohexenols, Catalyzed by Chromium- and Manganese-Substituted Polyoxometalates and Salen Complexes", Eur. J. Org. Chem. 2002, 941-946.

875. Adam, W.; Bheema, Rao; P.; Degen, H.-G.; Saha- Möller, C. R. "Asymmetric Weitz-Scheffer Epoxidation of a,b-Enones by Optically Active Hydroperoxides: Control of Enantioselectivity through Metal-Coordinated or Hydrogen-Bonded Templates", Eur. J. Org. Chem. 2002, 630-639.

873. Adam, W.; Bheema Rao, P.; Degen, H.-G.; Lévai, A.; Patonay, T.; Saha-Möller, C. R. "Asymmetric Weitz- Schefffer Epoxidation of Isoflavones with Hydroperoxides, Mediated by Optically Active Phase- Transfer Catalysts", J. Org. Chem. 2002, 67, 259-264.

869. Bolm, C.; Beckmann, O.; Kühn, T.; Palazzi, C.; Adam, W.; Bheema Rao, P.; Saha-Möller, C. R. "Influence of Hydroperoxides on the Enantioselectivity of the Metal-Catalyzed Asymmetric Baeyer-Villiger Oxidation and Epoxidation with Chiral Ligands", Tetrahedron: Asymmetry 2001, 12, 2441-2446.

868. Adam, W.; Saha-Möller, C. R.; Ganeshpure, P. A. "Synthetic Applications of Nonmetal Catalysts for Homogeneous Oxidation", Chem. Rev. 2001, 101, 3499- 3548.

867. Adam, W.; Saha-Möller, C. R.; Schmid, K. S. "The Synthesis of 4,6-Dideoxyfuranoses through the Regioselective and Diastereoselective Oxyfunctionalization of a Dimethylphenylsilyl- Substituted Chiral Homoallylic Alcohol", J. Org. Chem. 2001, 66, 7365-7371.

866. Adam, W.; Bargon, R. M. "Molybdenum-Catalyzed Episulfidation of (E)-Cycloalkenes with Elemental Sulfur", Chem. Commun. 2001, 1910-1911.

865. Makosza, M.; Adam, W.; Zhao, C.-G.; Surowiec, M. "Oxidation of Nitrobenzylic Carbanions with Dimethyldioxirane. New Synthesis of Quinomethanes and Nitrobenzylic Carbinols. First Examples of Methylation of Carbanions with Dimethyldioxirane", J. Org. Chem. 2001, 66, 55022.

862. Adam, W.; Peters, K.; Peters, E.-M.; Schambony, S. B. "Efficient Control of the Diastereoselectivity and Regioselectivity in the Singlet-Oxygen Ene Reaction of Chiral Oxazolidine-Substituted Alkenes by a Remote Urea NH Functionality. Comparison with Dimethyldioxirane and m-Chorobenzoic Acid Epoxidations", J. Am. Chem. Soc. 2001, 123, 7228- 7232.

858. Adam, W.; Bottke, N.; Engels, B.; Krebs, O."An Experimental and Computational Study on the Reactivity and Regioselectivity for the Nitrosoarene Ene Reaction: Comparison with Triazolinedione and Singlet Oxygen", J. Am. Chem. Soc. 2001, 123,5542-5548.

856. Adam, W., Bargon, R. M. "Episulfidation of Strained Cycloalkenes in the Thermolysis of 5-Aryloxy- 1,2,3,4-thiatriazoles", Eur. J. Org. Chem. 2001, 1959- 1962.

855. Patonay, T.; Adam, W.; Lévai, A.; Köver, P.; Németh, M.; Peters, E.-M..; Peters, K. "Chemo- and Diastereoselectivity in the Dimethyldioxirane Oxidation of 2,3-Dihydro-4H-1-benzothiopyran-4-ones and 4H-1- Benzothiopyran-4-ones. Unusual Reactivity of 4H-1- Benzothiopyran-4-one-1-Oxides", J. Org. Chem. 2001, 66, 2275-22280.

852. Adam, W., Bheema Rao, P.; Degen, H.-G.; Saha- Möller, C. R. "Asymmetric WeitzScheffer Epoxidation of Conformationally Flexible and Fixed Enones with Sterically Demanding Hydroperoxides Mediated by Optically Active Phase-Transfer Catalysts" Tetrahedron: Asymmetry, 2001, 12, 121-125.

848. Adam, W.; Schambony, S. "Diastereoselective Epoxidation of Oxazolidine-Substituted Alkenes by Dimethyldioxirane and m-Chlorobenzoic Acid: p-Facial Control through Hydrogen Bonding by the Urea Functionality", Org. Lett. 2001, 3, 79-82.

847. Adam, W. (Ed.), DFG Research Report on Peroxide Chemistry: Mechanistic and Preparative Aspects of Oxygen Transfer; Wiley-VCH: Weinheim, 2000.

845. Lévai, A.; Adam, W.; Jekö, J.; Patonay, T.; Székely, A.; Vass, E. B. "A Comparative Study of the Epoxidation of 2-Substituted Isoflavones by Dimethyldioxirane, Sodium Hypochlorite, and Alkaline Hydrogen Peroxide (Weitz-Scheffer Reaction)", J. Heterocycl. Chem. 2000, 37, 1065-1089.

840. Adam, W.; Degen, H.-G.; Pastor, A.; Saha-Möller, C. R.; Schambony, S. B.; Zhao, C.-G. "Preparative Use of Peroxidic Oxidants for Oxygen-Transfer Reactions". In DFG Research Report on Peroxide Chemistry: Mechanistic and Preparative Aspects of Oxygen Transfer; Adam, W., Ed; Wiley-VCH: Weinheim, 2000.

836. Adam, W.; Bottke, N.; Krebs, O. "Steric and Conformational Control of the Regioselectivities in the Ene Reaction with Trisubstituted Cycloalkenes - Comparison of the Enophiles Singlet Oxygen, Triazolinedione and Nitrosoarene", Org. Lett. 2000, 21, 3293-3296.

835. Adam, W.; Bach, R. D.; Dmitrenko, O.; Saha- Möller, C. R. "A Computational Study of the Hydroxy- Group Directivity in the Peroxyformic Acid Epoxidation of the Chiral Allylic Alcohol (Z)-3-Methyl-3-penten-2-ol: Control of Threo Diastereoselectivity through Allylic Strain and Hydrogen Bonding", J. Org. Chem. 2000, 65, 6715-6728.

833. Adam, W.; Bottke, N. "Hydroxy-Group Directivity in the Nitroso Ene Reaction: Diastereo- and Regioselective Amination of Chiral Allylic Alcohols", J. Am. Chem. Soc. 2000, 122, 9846-9847.

831. Adam, W.; Balci, M.; Kilic, H. "2,3- Dioxabicyclo[2.2.2]oct-7-en-5-one: Synthesis and Reactions of the Keto Endoperoxide of Phenol", J. Org. Chem. 2000, 65, 5926-5931.

830. Adam, W.; Hajra, S.; Herderich, M.; Saha-Möller, C. R. "A Highly Chemoselective Oxidation of Alcohols to Carbonyl Products with Iodosobenzene Diacetate Mediated by Chromium(III)(salen) Complexes: Synthetic and Mechanistic Aspects", Org. Lett. 2000, 2, 2773- 2776.


826. Adam, W.; Fröhling, B. "An a,a'-Dioxothione in the Reaction of Ninhydrin with Potassium Thiotosylate and its [4+2] Cycloaddition with trans-Cyclooctene", Org. Lett. 2000, 2, 2519-2522.


823. Nava Salgado, V.; Adam, W. "The Unexpected Reorganizations of a b-Lactone Aldolate to 1,3-Dioxan- 4-ones in the Reaction of 4-(1-Methylethyl)-3- [(phenylthio)methyl]-1-oxetan-2-one Lithium Enolate with Acetaldehyde", Eur. J. Org. Chem. 2000, 2529- 2533.


822. Adam, W.; Peters, K.; Peters, E.-M., Schambony, S. B. "Diastereoselective and Regioselective Singlet- Oxygen Ene Reaction of Oxazolidine-Substituted Alkenes: Control through Hydrogen Bonding Mediated by the Urea Functionality of Chiral Auxiliaries", J. Am. Chem. Soc. 2000, 122, 7610-7611.

818. Adam, W.; Bottke, N.; Krebs, O. "The New skew and the Established cis and gem Regioselectivities in the Ene Reaction of Trisubstituted Olefins: Comparison of the Singlet Oxygen, Triazolinedione, and Nitrosoarene Enophiles", J. Am. Chem. Soc. 2000, 122, 6791-6792.

814. Adam, W.; Bheema Rao, P.; Degen, H.-G., Saha- Möller, C. R. "Metal-Template Effect in the Asymmetric Weitz-Scheffer Epoxidation of a,b Enones by an Optically Active Hydroperoxide", J. Am. Chem. Soc. 2000, 122, 5654-5655.

808. Peters, K.; Peters, E.-M.; Güthlein, M.; Wirth, T.; Adam, W. "Crystal Structure of [4S-[3(2R*, 3Z, 5R*), 4R]]-3-[2,5-bis(acetyloxy)-1-oxo-3-hexenyl]-2,2- dimethyl-4-phenyl- oxazolidine,[C6H7O(OCOCH3)2][C3H3NO(CH3)2C6H5]" Z. Kristallogr. NCS 2000, 215, 383-384.

806. Adam, W.; Pastor, A.; Wirth, T. "Direct Amination of Olefins through Sequential Triazolinedione Ene Reaction and Carbanion-Assisted Cleavage of the N-N Urazole Bond" Org. Lett. 2000, 2, 1295-1297.

805. Adam, W.; Pastor, A.; Peters, K.; Peters, E.-M. "Opposite p-Face Selectivity for the DMD and m-CPBA Epoxidations of Chiral 2,2-Dimethyloxazolidine Derivatives of Tiglic Amides: Control by Steric Interactions versus Hydrogen Bonding", Org. Lett. 2000, 2, 1019-1022.

799. Peters, K.; Peters, E.-M.; Schambony, S. B.; Adam, W. "Crystal Structure of [2S-[2a(S*),4a]]-2-(1-hydroxy- 2-methyl-2-propenyl-N,4-diphenyl-3- oxazolidinecarboxamide, C3H4NO(C4H7O)(C6H5)(CONHC6H5)", Z. Kristallogr. NCS 2000, 215, 213-214.

798. Peters, K.; Peters, E.-M.; Adam, W.; Köver, P.; Lévai, A.; Patonay, T. “Crystal Structure of [1S, 2S]-cis- 6-Chloro-2-methyl-1-thiochroman-4-one 1-oxide, C9H6SO2(CH3)Cl, Z. Kristallogr. NCS 2000, 215, 217- 218.

797. Peters, K.; Peters, E.-M.; Adam,W.; Pastor, A.; Wirth, T. "Crystal Structure of [(S-(R*,2R*,3S*)]-2,2- Dimethyl-3-[(2,3-dimethyloxiranyl)carbonyl]4- phenyloxazolidine, [(C3H3NO)(CH3)2(C6H5)]CO[C2HO(CH3)2], Z. Kristallogr. NCS 2000, 215, 211-212.

793. Adam, W.; Gadissa Gelalcha, F.; Saha-Möller, C. R., Stegmann, V. "Chemoselective
C-H Oxidation of Alcohols to Carbonyl Compounds with Iodosobenzene Catalyzed by (Salen)chromium Complex", J. Org. Chem. 2000, 65, 1915-1918.

795. Peters, K.; Peters, E.-M.; Adam, W.; Köver, P.; Lévai, A.; Patonay, T. “Crystal Structure of [1S*, 2S*]- trans-6-chloro-2-methyl-1-thiochroman-4-one 1-oxide, C9H6SO2(CH3)Cl, Z. Kristallogr. NCS 2000, 215, 219- 220.

791. Adam, W.; Makosza, M.; Zhao, C.-G.; Surowiec, M. "On the Mechanism of the Dimethyldioxirane Oxidation of sH Adducts (Meisenheimer Complexes) Generated from Nitroarenes and Carbanions" J. Org. Chem. 2000, 65, 1099-1101.

790. Adam, W.; Saha-Möller, C. R.; Schmid, K. S. "Preparation of Optically Active Allylic Hydroperoxy Alcohols and 1,3 Diols by Enzyme-Catalyzed Kinetic Resolution and Photooxygenation of Chiral Homoallylic Alcohols", J. Org. Chem. 2000, 65, 1431-1433.

780. Adam, W.; Saha-Möller, C. R.; Schambony, S.; Schmid, K. S.; Wirth, T. "Stereocontrolled Photooxygenations – A Valuable Synthetic Tool", Photochem. Photobiol. 1999, 70, 476-483.

779. Adam, W.; Saha-Möller, C. R.; Zhao, C.-G. "Asymmetric C-H Oxidation of vic Diols to a-Hydroxy Ketones by a Fructose-Derived Dioxirane: Electronic Effects on the Enantioselectivity of Oxygen Transfer", J. Org. Chem. 1999, 64, 7492-7497.

775. Adam, W.; Saha-Möller, C. R.; Zhao, C.-G. "Asymmetric Epoxidation of Olefins by Chiral Dioxiranes Generated in situ From Ketones of D-(-)-Quinic Acid", Tetrahedron: Asymmetry 1999, 10, 2749-2755.

773.Rodriguez, G.; Castedo, L.; Dominguez, D.; Sáa, C., Adam, W. "Regioselective Synthesis of Isoquino[1,2-b][3]benzazepines (Homoprotoberberines) through 11-Membered-Ring Stilbene Lactams Obtained by Radical Macrocyclization", J. Org. Chem. 1999, 64, 4830-4833.

772. Adam, W.; Wirth, T. "Hydroxy Group Directivity in the Epoxidation of Chiral Allylic Alcohols: Control of Diastereoselectivity through Allylic Strain and Hydrogen Bonding", Acc. Chem. Res. 1999, 32, 703-710.

771. Wilsey, S.; Bernardi, F.; Olivucci, M.; Robb. M. A.; Murphy, S.; Adam, W. "The Thermal Decomposition of 1,2-Dioxetane Revisited", J. Phys. Chem. A 1999, 103, 1669-1677.

770. Adam, W.; Bottke, N.; Krebs, O.; Saha-Möller, C. R. "Allylic Amidation of Olefins by Ene Reaction of Acylnitroso Compounds Generated in situ by Oxidation of Hydroxamic Acids", Eur. J. Org. Chem. 1999, 1963-1965.

760. Peters, K.; Peters, E.-M.; Fröhling, B.; Weinkötz, S.; Adam, W. "Crystal Structure of trans-9-Thiabicyclo[6.1.0]nonan-3-ol, C8H13(S)OH", Z. Kristallogr. 1999, 275-276.

 

756. Adam, W.; Saha-Möller, C. R.; Schambony, S. B. "A Highly Diastereoselective Dioxetane Formation by the Hydroxy-Directed [2+2] Cycloaddition of Singlet Oxygen to a Chiral Allylic Alcohol", J. Am. Chem. Soc. 1999, 121, 1834-1838.

753. Adam, W.; Degen, H.-G.; Saha-Möller, C. R. "Regio- and Diastereoselective Catalytic Epoxidation of Chiral Allylic Alcohols with Hexafluoroacetone Perhydrate. Hydroxy-Group Directivity through Hydrogen Bonding" J. Org. Chem. 1999, 64, 1274-1277.

750. Rodriguez, G.; Castedo, L., Dominguez, D.; Saá, C.; Adam, W.; Saha-Möller, C. R. "Dioxirane Epoxidation of 10-Membered-Ring Stilbene Lactams as Synthetic Precursors to Protoberberines", J. Org. Chem. 1999, 64, 877-883.

748. Peters, K.; Peters, E.-M.; Adam, W.; Pastor, A.; Wirth, Th. "Crystal Structure of [S-(R*, R*)]-1-[3-(2,2-Dimethyl-4-phenyloxazolidine-3-yl]-1-methyl-2-[methylidene-3-oxopropyl]-4-phenyl-1,2,4-triazolidine-3,5-dione, C11H14NO[C5H6O)C8H6N3O2, Z. Kritallogr. 1999, 87-88.

747. Adam, W.; Fröhling, B.; Weinkötz, S. "Thermal and Photochemical 1,3-Dipolar Cycloaddition of a Sulfine (Fluorenethione S-oxide) to the Strained Triple Bond of Cyclooctyne", J. Org. Chem. 1998, 63, 9154-9155.

746. Adam, W.; Saha-Möller, C. R.; Zhao, C.-G. "Enantioselective Oxidation of vic-Diols to Optically Active a-Hydroxy Ketones by a Fructose-derived Dioxirane", Tetrahedron: Asymmetry 1998, 9, 4117-4122.

745. Adam, W.; Makosza, M.; Saha-Möller, C. R.; Zhao, C.-G. "A Mild and Efficient Nef Reaction for the Conversion of Nitro to Carbonyl Group by Dimethyldioxirane (DMD) Oxidation of Nitronate Anions", Synlett 1998, 1335-1336.

741. Adam, W.; Balci, M.; Kiliç, H. "Oxyfunctionalization of Biphenylene by Singlet Oxygen, Hydrogen Peroxide/Methyltrioxorhenium, and Dimethyldioxirane", J. Org. Chem. 1998, 63, 8544-8546.

735. Ferrer, M.; Sánchez-Baeza, F.; Messeguer, A., Adam, W. Golsch, D.; Görth, F.; Kiefer, W.; Nagel, V. "The Release of Singlet Oxygen in the Reaction of Dioxiranes with Amine N-Oxides", Eur. J. Chem. 1998, 2527-2532.

727. Adam, W.; Fröhling, B.; Peters, K.; Weinkötz, S. "Diastereoselective Episulfidation of Strained Cyclic Alkenes by a Thiophene Endoperoxide versus Epoxidation by Dimethyldioxirane", J. Am. Chem. Soc. 1998, 120, 8914-8919.

722. Adam, W.; Makosza, M.; Stalinski, K.; Zhao, C.-G. "DMD Oxidation of in-situ- Generated sH Adducts Derived from Nitroarenes and the Carbanion of 2-Phenylpropionitrile to Phenols: The First Direct Substitution of a Nitro by a Hydroxy Group, J. Org. Chem. 1998, 63, 4390-4391.

720. Adam, W.; Weinkötz, S. "1,3-Dipolar Cycloaddition of Fluorenethione S-Oxide and trans-Cyclooctene: Isolation of a Sultene and Its Novel Acid-Catalyzed Diastereoselective Sulfur-Atom Transfer to Cyclic Olefins", J. Am. Chem. Soc. 1998, 120, 4861-4862.

718. Adam, W.; Güthlein, M.; Peters, E.-M.; Peters, K.; Wirth, T. "Chiral Auxiliary-Induced Diastereoselectivity in the [4+2] Cycloadditions of Optically Active 2,2-Dimethyloxazolidine Derivatives of Sorbic Acid: A Model Study with Singlet Oxygen as the Smallest Dienophile", J. Am. Chem. Soc. 1998, 120, 4091-4093.

715. Nagel, V.; Duschek, F.; Kiefer, W.; Görth, F.; Golsch, D.; Adam,W.; Ferrer, M.; Messeguer, A. "Detection of Singlet Oxygen During Several Organic Reactions by Chemiluminescence Spectroscopy", Asian Journal of Spectroscopy 2 1998, 35-43.

713. Adam, W.; Wirth, T.; Pastor, A.; Peters, K. "Dramatic Diastereoselectivity Difference in the Asymmetric Ene Reactions of Triazolinediones and Singlet Oxygen with Chiral 2,2-Dimethyloxazolidine Derivatives of Tiglic Acid", Eur. J. Org. Chem. 1998, 791-796.

712. Aubry, J. M.; Nardello, V.; Bouttemy, S.; Wirth, T.; Linker, T.; Adam, W. "The Luminous and the Dark Side of Singlet Oxygen: Comparison Between Photochemical and Chemical Sources of Singlet Oxygen (1O2, 1Dg) in Organic Synthesis". In Selective Reactions of Metal-Activated Molecules; Werner, H., Schreier, P., Eds.; Vieweg Verlag: Braunschweig, 1998; pp. 277-281.

710. Schenk, W. A.; Dürr, M.; Steinmetz, B.; Adam, W.; Saha-Möller, C. R. "Enantioselective Oxidation of Thioethers Using Ruthenium Complexes as Chiral Auxiliary". In Selective Reactions of Metal-Activated Molecules; Werner, H., Schreier, P., Eds.; Vieweg Verlag: Braunschweig, 1998, pp. 245-249.

705. Adam, W.; Nestler, B.; Pastor, A.; Wirth, T. "Hydroxy-Directed Diastereoselective Ene Reaction of Triazolinediones with Chiral Allylic Alcohols", Tetrahedron Lett. 1998, 39, 2625-2628.

694. Adam, W.; Fell, R. T.; Saha-Möller, C. R.; Zhao, C.-G. "Synthesis of Optically Active a-Hydroxy Ketones by Enantioselective Oxidation of Silyl Enol Ethers with a Fructose-Derived Dioxirane", Tetrahedron: Asymmetry 1998, 9, 397-401.

690. Adam, W.; Renze, J.; Wirth, T. "Stereoelectronic Control of the Diastereoselectivity in the Photooxygenation (Schenck Ene Reaction) of an Electron-Poor Allylic Alcohol and its Ethers", J. Org. Chem. 1998, 63, 226-227.

689. Adam, W.; Paredes, R.; Smerz, A. K.; Veloza, L. A. "Regio- and Diastereo- and Chemoselectivities in the Dioxirane Oxidation of Acyclic and Cyclic Allylic Alcohols by Methyl(trifluoromethyl)dioxirane (TFD): A Comparison with Dimethyldioxirane", Liebigs. Ann. Chem. 1998, 2, 349-354.

685. Adam, W.; Zhao, C.-G. "Synthesis of Optically Active C2-Symmetric Ketones for the Asymmetric Epoxidation of Prochiral Olefins by Dioxiranes Generated in situ with CaroateTM as Peroxide Source",Tetrahedron: Asymmetry 1997, 8, 3995-3998.

680. Adam, W.; Wirth, T. "Steric and Stereoelectronic Effects in the Diastereoselective Photooxygenation (Schenk Ene Reaction) of Acyclic Chiral Alkenes", In Actas de la 26a Reunion Bienal de la Real Sociedad Espanola de Quimica, Gordillo, C. M., Ed.; Servicio de Publicones de la Universidad de Cadiz: Cadiz, 1997; Vol.1, pp 191-198.

676. Adam, W.; Deeg, O.; Weinkötz, S. "Direct Thioepoxidation of Strained Cyclic Alkenes by the Photolytic Sulfur-Atom Transfer from Thiocarbonyl S-Oxides (Sulfines)", J. Org. Chem. 1997, 62, 7084-7085.

665. Schenk, W. A.; Frisch, J.; Dürr, M.; Burzlaff, N.; Stalke, D.; Fleischner, R.; Adam, W.; Prechtl, F.; Smerz, A. "Oxidation of Thioether Ligands in Pseudotetrahedral Cyclopentadienylruthenium Complexes: Toward a New Stereoselective Synthesis of Chiral Sulfoxides", J. Inorg. Chem. 1997, 36, 2372-2378.

653. Adam, W.; Blancafort, L. "Reaction of a-Peroxy Lactones with C,N,P and S Nucleophiles: Adduct Formation and Nucleophilic Oxidation by Nucleophilic Attack and Biphilic Insertion into the Peroxide Bond", J. Org. Chem. 1997, 62, 1623-1629.

652. Adam, W.; Smerz, A. K.; Zhao, C.-G. "Dioxiranes - Highly Reactive Oxidants for Stereoselective Oxyfunctionalizations", J. prakt. Chem. 1997, 339, 298-300.

651. Adam, W.; Lévai, A.; Mérour, J.-Y.; Nemes, C.; Patonay, T. "Dioxirane Oxidation of 2-Arylidene-2,3-dihydro-1H-indol-3-ones. Diastereoselective Formation of Spiro Epoxides", Synthesis 1997, 268-270.

650. Adam, W.; Paredes, R.; Smerz, A.K.; Veloza, L.A. "Probing for Steric and Electronic Effects in Diastereoselective Dioxirane Epoxidations Compared to the Oxygen Transfer by Peroxy Acids", Liebigs Ann. Chem. 1997, 547-551.

643. Schulz, M.; Liebsch, S.; Kluge, R.; Adam, W. "Organo Sulfonic Peracids, 41: The Reaction of Arenesulfonylimidazoles with H2O2 in the Presence of Ketones - A New Entry to Dioxiranes", J. Org. Chem. 1997, 62, 188-193.

642. Adam,W.; Golsch, D. "Probing for Electronic and Steric Effects in the Peracid Oxidation of Thianthrene 5-Oxide", J. Org. Chem. 1997, 62, 115-119.

641. Adam, W.; Curci, R.; D’Accolti, L.; Dinoi, A.; Fusco, C.; Gasparrini, F.; Kluge, R.; Paredes, R.; Schulz, M.; Smerz, A. K.; Veloza, L. A.; Weinkötz, S.; Winde, R. "Epoxidation and Oxygen Insertion into Alkane CH Bonds by Dioxirane Do Not Involve Detectable Radical Pathways", Chem. Eur. J. 1997, 3, 105-109.

636. Adam, W.; Putterlik, J.; Schuhmann, R. M.; Sundermeyer, J. "Synthesis of Tris(pyrazolyl)borate-Stabilized Vinyl, Allyl and Homoallyl Tungsten Oxides and Their Selective Oxyfunctionalization by Singlet Oxygen and Dioxirane", Organometallics 1996, 15, 4586-4596.

633. Adam, W.; Blancafort, L. "Stereoselective Cycloaddition and Epoxidation of Enol Ethers by a-Peroxy Lactone as a Function of Steric and Stereoelectronic Effects", J. Org. Chem. 1996, 61, 8432-8438.

626. Adam, W.; Smerz, A. K. "Chemistry of Dioxiranes: Selective Oxidations", Bull. Soc. Chim. Belg. 1996, 105, 581-599.

625. Adam, W.; Golsch, D.; Sundermeyer, J.; Wahl, G. "Activation of Bis(trimethylsilyl) Peroxide and tert-Butyl Hydroperoxide with Oxo and Peroxo Complexes of Vanadium, Molybdenum and Tungsten for the Sulfoxidation of Thianthrene 5-Oxide", Chem. Ber. 1996, 129, 1177-1182.

624. Adam, W.; Jekö, J.; Lévai, A.; Majer, Z.; Nemes, C.; Patonay, T.; Párkányi, L.; Sebök, P. "Determination of the Absolute Configuration of Optically Active 2,2-Dimethyl-3,4-epoxychromans Prepared by the Catalytic Enantioselective Epoxidation with the Dimethyldioxirane/Jacobsen Mn(II)salen System", Tetrahedron: Asymmetry 1996, 7, 2437-2446.

620. Voigt, B.; Porzel, A.; Golsch, D.; Adam, W.; Adam, G. "Regioselective Oxyfunctionalization of Brassinosteroids by Methyl(trifluoromethyl)dioxirane: Synthesis of 25-Hydroxybrassinolide and 25-Hydroxy-24-epibrassinolide by Direct CH Insertion", Tetrahedron 1996, 52, 10653-10658.

619. Patonay, T.; Lévai, A.; Nemes, C.; Timár, T.; Tóth, G.; Adam, W.; "Synthesis and Cyclization of 1-(2-Hydroxyphenyl)-2-propene-1-one Epoxides: 3-Hydroxychromanones and -flavones versus 2-(1-Hydroxyalkyl)-3-coumaranones", J. Org. Chem. 1996, 61, 5375-5383

617. Adam, W.; Halász, J.; Jámbor, Z.; Lévai, A.; Nemes, C.; Patonay, T.; Tóth, G. "Stereoselective Epoxidation of 2-Arylidene-1-indanones and 2-Arylidene-1-benzosuberones", Monatshefte 1996, 127, 683-690.

612. Adam, W.; Blancafort, L. "Steric and Stereoselective Control of the Mode Selectivity as a Function of Alkene Structure in the Reaction with Dimethyl a-Peroxy Lactone: Cycloadducts and Ene Products versus Epoxides, J. Am. Chem. Soc. 1996, 118, 4778-4787.

611. Adam, W.; Smerz, A. K. "Solvent Effects in the Regio- and Diastereoselective Epoxidations of Acyclic Allylic Alcohols by Dimethyldioxirane: Hydrogen Bonding as Evidence for a Dipolar Transition State", J. Org. Chem. 1996, 61, 3506-3510.

610. Adam, W.; Prein, M. "The p-Facial Diastereoselectivity in the [4+2] Cycloaddition of Singlet Oxygen as Mechanistic Probe", Acc. Chem. Res. 1996, 29, 275-283.

603. Adam, W.; Smerz, A. K. "Nickel-Catalyzed Hydroxylation of 1,3-Dicarbonyl Compounds by Dimethyldioxirane", Tetrahedron 1996, 52, 5799-5804.

601. Adam, W.; Schuhmann, R. "Selective Oxyfunctionalization of (Tricarbonyl-cyclohexadien)iron-Substituted Furans with Singlet Oxygen and Dimethyldioxirane", Liebigs Ann. Chem. 1996, 635-640.

600. Lévai, A.; Adam, W.; Jekö, J.; Nemes, C.; Patonay, T. "Dimethyldioxirane Epoxidation of Chalcone and Isoflavone Glycoside Acetates". In Flavonoids and Bioflavonoids. Proceedings of the International Bioflavonoid Symposium, Vienna, Austria; Antus, S., Gabor, M., Vetschera, K., Eds; Akadémiai Kiado: Budapest, 1996; pp 167-176.

599. Patonay, T.; Adam, W.; Halász, J.; Lévai, A.; Nemes, C.; Tóth, G. "Oxidations of Benzopyrans, Benzofurans and Related Compounds: One Step Ahead". In Flavonoids and Bioflavonoids. Proceedings of the International Bioflavonoid Symposium, Vienna, Austria; Antus, S., Gabor, M., Vetschera, K., Eds; Akadémiai Kiado: Budapest, 1996; pp 329-333.

595. Ganeshpure, P.A.; Adam, W. "a-Hydroxy Hydroperoxides (Perhydrates) as Oxygen Transfer Agents in Organic Synthesis", Synthesis 1996, 179-188.

594. Malisch, W.; Hindahl, K.; Grün, K.; Adam, W.; Prechtl, F.; Sheldrick, W.S. "Synthese und Reaktivität von Übergangsmetall-substituierten Phosphanen, Arsanen und Stibanen LVII. Oxidation tertiärer und sekundärer Metallphosphane von Eisen und Wolfram mit Dimethyldioxiran" J. Organomet. Chem. 1996, 509, 209-214.

593. Adam, W.; Golsch, D.; Görth, F.C. "Thianthrene 5-Oxide as a Mechanistic Probe in Oxygen-Transfer Reactions: The Case of Carbonyl Oxides versus Dioxiranes Revisited", Chem. Eur. J. 1996, 2, 255-258.

592. Adam, W.; Halász, J., Jámbor, Z.; Lévai, A., Nemes, C.; Patonay, T.; Tóth, G. "Synthesis and Stereochemistry of the Epoxides of 2-Arylmethylidene-1-tetralones", J. Chem. Soc., Perkin Trans. 1, 1996, 4, 395-400.

591. Adam, W.; Brünker, H.-G.; Sampath Kumar, A.; Peters, E.-M.; Peters, K.; Schneider, U.; von Schnering, H.G. "Diastereoselective Singlet Oxygen Ene Reaction (Schenck Reaction) and Diastereoselective Epoxidations of Heteroatom-Substituted Acyclic Chiral Olefins: A Mechanistic Comparison", J. Am. Chem. Soc. 1996, 118, 1899-1905.

588. Prein, M.; Adam, W. "The Schenck Ene Reaction: Diastereoselective Oxyfunctionalization with Singlet Oxygen in Synthetic Applications", Angew. Chem. 1996, 108, 519-538; Angew. Chem., Int. Ed. Engl. 1996, 35, 477-494.

587. Adam, W.; Schuhmann, R.M. "Iron Tricarbonyl Complexes in Oxidation Chemistry: Regio- and Stereoselective Oxyfunctionalization of Trienes by Singlet Oxygen and Dimethyldioxirane", J. Org. Chem. 1996, 61, 874-878.

586. Adam, W.; Weinkötz, S. "Synthesis of Thiiranes through Direct Sulfur Transfer to Cycloalkanes in the Thermolysis of a Thiophene Endoperoxide", J. Chem. Soc., Chem. Commun. 1996, 177-178.

585. Adam, W.; van Barneveld, C.; Golsch, D. "Direct Synthesis of 3-Aryl-1,2,4,5-tetrazine N-1-Oxides by the Oxidation with Methyl(trifluoromethyl)dioxirane", Tetrahedron 1996, 52, 2377-2384.

583. Lévai, A.; Adam, W.; Halász, J.; Nemes, C.; Patonay, T.; Tóth, G. "Dioxirane Oxidation of Benzopyranes, Benzothiopyrans and Related Comp.", Chem. Heterocycl. Compounds 1995, 10, 1345-1349.

581. Adam, W.; Ganeshpure, P. "Bis(trimethylsilyl) Monoperoxysulfate (CH3)3SiOSO2OOSi(CH3)3". In Encyclopedia of Reagents for Organic Synthesis; Paquette, L. A., Ed.; John Wiley and Sons: Chichester; 1995; Vol. 1, pp. 599-600.

580. Adam, W.; Kumar, A. S.; Saha-Möller, C. R. "Synthesis of a-Methylene-b-hydroperoxy Sulfoxides by Regioselective Photooxygenation (Schenck Reaction) of Racemic Vinyl Sulfoxides", Synthesis 1995, 1525-1528.

579. Adam, W.; Griesbeck, A. "Allylic Oxidation with Singlet Molecular Oxygen". In Methods of Organic Chemistry (Houben Weyl), Stereoselective Synthesis. Helmchen, G., Hoffmann, R. W., Mulzer, J. E., Schaumann, E., Eds.; Georg Thieme Verlag: Stuttgart, 1995; Vol. E21e, pp 4928-4946.

575. Malisch, W.; Schmitzer, S.; Lankat, R.; Neumayer, M.; Prechtl, F.; Adam, W. "Metallo-silanole vom Typ C5R5(OC)2(Me3P)M-SiPh2OH (M=Cr, Mo, W): Darstellung nach der Dimethyldioxiranmethode und Überführung in funktionalisierte Metallo-disiloxane", Chem. Ber. 1995, 128, 1251-1255.

574. Malisch, W.; Neumayer, M.; Fey, O.; Adam, W.; Schuhmann, R. "Synthese des diastereomerenreinen Ferrio-silanols (RS,SR)-Cp (OC) (Ph3P)Fe-Si(Me)(Ph)(OH) und Struktur von (RR,SS)-Cp(OC)(Ph3P)Fe-Si(Me)(Ph)Cl", Chem. Ber. 1995, 128, 1257-1260.

572. Adam, W.; Smerz, A. K. "Solvent Effects in the Dimethyldioxirane Oxidation of Allylic Alcohols: Evidence for Hydrogen Bonding in the Dipolar Transition State of Oxygen Transfer", Tetrahedron 1995, 51, 13039-13044.

571. Adam, W.; Prein, M. "p-Facial Selectivity of the Singlet Oxygen [4+2]-Cycloaddition to Chiral Naphthalene Derivatives: The Directing Effect of Carbon-Containing Substituents", Tetrahedron 1995, 51, 12583-12590.

570. Adam, W.; Reinhardt, D.; Reissig, H.-U.; Paulini, K. "Epoxidation of Vinylamides by Dimethyldioxirane: First Spectral Evidence for Enamide Oxides", Tetrahedron 1995, 51, 12257-12262.

569. Adam, W.; Kumar, A.S.; Saha-Möller, C. R. "Photooxygenation of Vinyl Sulfides: Substituent Effects on the [2+2]-Cycloaddition versus Schenck-Reaction Modes", Tetrahedron Lett. 1995, 36, 7853-7854.

568. Adam, W.; Briviba, K.; Duschek, F.; Golsch, D.; Kiefer, W.; Sies, H. "Formation of Singlet Oxygen in the Deoxygenation of Heteroarene N-Oxides by Dimethyldioxirane", J. Chem. Soc., Chem. Commun. 1995, 1831-1832.

565. Adam, W.; Weinkötz, S. "Triphenylphosphine Reduction of Thiophene Endoperoxides: Nucleophilic Attack on Sulfur versus Biphilic Insertion into the Peroxide Bond", Tetrahedron Lett. 1995, 36, 7431-7432.

562. Adam, W.; Brünker, H.-G. "Diastereoselective Synthesis of Merucathin: The Singlet-Oxygen Ene Reaction (Schenck Reaction) as Key Step Towards an E-Configured b-Amino Allylic Alcohol", Synthesis 1995, 1066-1068.

561. Malisch, W.; Hindahl, K.; Käb, G.; Reising, J.; Adam, W.; Prechtl, F. "Die ersten Hydroxysilandiyl-verbrückten Zweikernkomplexe: Selektive Oxygenierung der Silicium-Brücke in Silandiyleisen-Komplexen mit Dimethyldioxiran", Chem. Ber. 1995, 128, 963-965.

560. Adam, W.; Gläser, J.; Peters, K.; Prein, M. "Highly like-Selective [4+2] Cycloadditions of Chiral Dienols: The Importance of 1,3-Allylic Strain in the Hydroxy-Directed Stereocontrol", J. Am. Chem. Soc. 1995, 117, 9190-9193.

554. Adam, W.; Jekö, J.; Lévai, A.; Nemes, C.; Patonay, T. "Dimethyldioxirane Epoxidation of Chalcone and Isoflavone Glycoside Acetates", Liebigs. Ann. Chem. 1995, 1547-1549.

553. Adam, W.; Sauter, M. "Oxyfunctionalization of Benzofurans by Singlet Oxygen, Dioxiranes, and Peracids: Chemical Model Studies for the DNA-Damaging Activity of Benzofuran Dioxetanes (Oxidation) and Epoxides (Alkylation), Acc. Chem. Res. 1995, 28, 289-298.

552. Adam, W.; Prechtl, F.; Richter, M. J.; Smerz, A. K. "Epoxidation versus Allylic Oxidation (CH Insertion) in the Oxyfunctionalization of Vinylsilanes and b-Hydroxy Derivatives by Dimethyldioxirane", Tetrahedron Lett. 1995, 36, 4991-4994.

548. Adam, W.; Peters, E. M.; Peters, K.; Prein, M.; von Schnering, H.G. "Diastereoselective Photooxygenation of Chiral Naphthyl Alcohols: The Hydroxy-Group-Directing Effect in the Singlet Oxygen [4+2] Cycloaddition to Arenes", J. Am. Chem. Soc. 1995, 117, 6686-6690.

543. Adam, W.; Jacob, U.; Prein, M. "Importance of Steric Effects in the [4+2] Cycloaddition of 5-Substituted Pentamethylcyclopentadienes", J. Chem. Soc., Chem. Commun. 1995, 839-840.

542. Adam, W.; Stössel, R.; Treiber, A. "The SN2 Reactivity of 3,3-Disubstituted 1,2-Dioxetanes with Morpholine", J. Org. Chem. 1995, 60, 2879-2884.

539. Schulz, M.; Kluge, R.; Schüßler, M.; Adam, W.; Prechtl, F. "Stereoselective a Hydroxylation of Ketones via Titanium Enolates by Using Organic Peroxides". In Selective Reactions of Metal-Activated Molecules. Sundermeyer, J., Werner, H., Eds.; Vieweg Verlag: Braunschweig 1995, pp.45-48.

538. Adam, W.; Brünker, H.-G.; Golsch, D.; Klug, P.; Lin, J.; Mitchell, C.; Prechtl, F.; Prein, M.; Renz, M.; Richter, M.; Saha-Möller, C. R.; Schuhmann, R.; Shimizu, M.; Smerz, A., Hoch, U.; Schreier, P. "Selective Oxygen Transfer". In Selective Reactions of Metal-Activated Molecules. Sundermeyer, J., Werner, H., Eds.; Vieweg Verlag: Braunschweig 1995, pp. 39-44.

536. Brünker, H.-G.; Adam, W. "Diastereoselective and Regioselective Singlet Oxygen Ene Oxyfunctionalization (Schenck Reaction): Photooxygenation of Allylic Amines and Their Acyl Derivatives", J. Am. Chem. Soc. 1995, 117, 3976-3982.

535. Prein, M.; Maurer, M.; Peters, E.-M.; Peters, K.; von Schnering H. G.; Adam, W. "Diastereoselective Synthesis of 4-Hydroperoxy-3,5-cyclohexadiones in the Photooxygenation of Hydroxyethyl-Substituted Phenols", Chem. Eur. J. 1995, 1, 89-94.

534. Adam, W.; Treiber, A. "Oxidation of Acetylated Guanosine by 3,3-Disubstituted 1,2-Dioxetanes through Nucleophilic Attack on the Peroxide Bond: Model Studies on the Oxidative DNA Damage by Reactive Peroxides", J. Am. Chem. Soc. 1995, 117, 2686-2693.

531. Adam, W.; Ahrweiler, M.; Balci, M.; Cakmak, O.; Saha-Möller, C. R.; "Rearrangement and Valence Isomerization in the Dimethyldioxirane Epoxidation of 2,3,5,6-Tetramethoxybenzobarrelene to Benzonorcaradiene endo-Ester", Tetrahedron Lett. 1995, 36, 1429-1430.

524. Adam, W.; Schuhmann, R. M."Synthesis of Epoxyferrocenes by the Oxidation of Acyl- and Allyl Substituted Ferrocenes with Dimethyldioxirane", J. Organomet. Chem. 1995, 273-277.


Last Change: 11.11.2003