Asymmetric epoxidation of nonfunctionalized alkenes with high enantioselectivity using chiral sulfamyloxaziridines

Davis, Franklin A.; Chattopadhyay, Sankar

doi:10.1016/s0040-4039(00)85137-0

Cited by 42 publications

(4 citation statements)

References 9 publications

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“…The pentafluorobenzaldehyde when treated the toluenesulfonamide yields 79% N-tosyl-pentafluorobenzylidene amine (Scheme 43 [501][502][503]). …”

Section: Chemical Reactions Of Pentafluorobenzaldehyde With Nitrogen mentioning

confidence: 99%

Pentafluorobenzaldehyde and its utilizing in organic synthesis

Pažitný

Solčan

Végh

2009

Journal of Fluorine Chemistry

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“…The pentafluorobenzaldehyde when treated the toluenesulfonamide yields 79% N-tosyl-pentafluorobenzylidene amine (Scheme 43 [501][502][503]). …”

Section: Chemical Reactions Of Pentafluorobenzaldehyde With Nitrogen mentioning

confidence: 99%

Pentafluorobenzaldehyde and its utilizing in organic synthesis

Pažitný

Solčan

Végh

2009

Journal of Fluorine Chemistry

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“…The asymmetric epoxidation of styrenes also has received a considerable amount of interest. Various chiral catalysts and reagents have been investigated for the epoxidation of styrenes, including chiral porphyrin complexes (16 -34), chiral salen complexes (35)(36)(37)(38)(39)(40)(41)(42), chiral oxaziridines and oxaziridinium salts (43)(44)(45)(46), and enzymes (47)(48)(49)(50)(51). Metal catalysts such as chiral porphyrin and salen complexes have been studied extensively for the epoxidation of these alkenes, and the enantioselectivities have reached the 80% range in a number of cases (21,23,29,31,37,38,40,41), with 96% enantiomeric excess (ee) being obtained in one case (3,5-dinitrostyrene) (23).…”

mentioning

confidence: 99%

Highly enantioselective epoxidation of styrenes: Implication of an electronic effect on the competition between spiro and planar transition states

Hickey

Goeddel

Crane

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Asymmetric epoxidation of various styrenes using carbocyclic oxazolidinone-containing ketone 3 has been investigated. High enantioselectivity (89 -93% enantiomeric excess) has been attained for this challenging class of alkenes. Mechanistic studies show that substituents on the ketone catalyst can have electronic influences on secondary orbital interactions, which affects the competition between spiro and planar transition states and, ultimately, enantioselectivity. The results described herein not only reveal the potential of chiral dioxirane catalyzed asymmetric epoxidation as a viable entry into this important class of olefins but also further enhance the understanding of the mechanistic aspects of chiral ketone-catalyzed asymmetric epoxidation. Epoxides are important intermediates for the synthesis of complex molecules. Asymmetric epoxidation of prochiral alkenes presents a powerful strategy for the synthesis of enantiomerically enriched epoxides. Great progress has been made in the areas of asymmetric epoxidation of allylic alcohols (1-3), chiral metal complex-catalyzed epoxidation of unfunctionalized alkenes (particularly with conjugated cis-and trisubstituted alkenes) (4 -7), and asymmetric epoxidation of electron-deficient alkenes under nucleophilic conditions (8 -10). Styrene oxides are extremely useful and can be prepared by a number of methods such as asymmetric reduction of ␣-halo acetophenones (refs. 11 and 12 and references therein), asymmetric dihydroxylation of styrenes (13,14), and kinetic resolution of racemic epoxides (15). The asymmetric epoxidation of styrenes also has received a considerable amount of interest. Various chiral catalysts and reagents have been investigated for the epoxidation of styrenes, including chiral porphyrin complexes (16 -34), chiral salen complexes (35-42), chiral oxaziridines and oxaziridinium salts (43-46), and enzymes (47-51). Metal catalysts such as chiral porphyrin and salen complexes have been studied extensively for the epoxidation of these alkenes, and the enantioselectivities have reached the 80% range in a number of cases (21,23,29,31,37,38,40,41), with 96% enantiomeric excess (ee) being obtained in one case (3,5-dinitrostyrene) (23).Among other oxidants, dioxiranes either isolated or generated in situ are powerful epoxidation agents (Scheme 1; refs. 52-54). Chiral dioxiranes were shown recently to be effective for asymmetric epoxidation of trans-, trisubstituted (55-91), and certain cis-alkenes (92-95). Asymmetric epoxidation of styrenes with chiral dioxiranes has been studied also (61,66,68,81,88,90,(93)(94)(95); however, the enantioselectivity has not exceeded 85% (93-95). Generally speaking, the highly enantioselective epoxidation of styrenes still remains a formidable challenge.During our studies, we found that varying the catalyst structure could have a dramatic effect on enantioselectivity for the dioxirane-mediated epoxidation of styrene. Fructosederived ketone 1 (Scheme 2), a very effective catalyst for transand trisubstituted alkenes, gave only 24...

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“…The most exploited strategy to access chiral oxaziridines consists of the oxidation of chiral imines with MCPBA or peroxymonosulfate (oxone). Acyclic imines usually afford mixtures of diastereoisomers that could be separated by fractional crystallization or chromatography, ,,− as reported in Scheme . The best diastereoselectivities have been generally achieved with cyclic substrates, even though, in most instances, recrystallization is required to obtain optically pure products. ,− …”

Section: Asymmetric Synthesis Of Oxaziridinesmentioning

confidence: 99%

Asymmetric Catalytic Routes to Dialkyl Peroxides and Oxaziridines

Sala

Lattanzi

2014

ACS Catal.

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Enantioenriched dialkyl peroxides and oxaziridines are two classes of compounds showing important biological activities, being useful synthetic intermediates and reagents for asymmetric oxidations and cycloaddition reactions. Chiral substrate-controlled diastereoselective preparations of these compounds have been developed almost exclusively in the last decades. The aim of this perspective article is to provide the reader with recent efforts devoted to addressing the challenging task of their synthesis via either enantioselective organo- and transition metal-catalyzed oxidations or via alternative nonoxidative approaches.

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Asymmetric epoxidation of nonfunctionalized alkenes with high enantioselectivity using chiral sulfamyloxaziridines

Cited by 42 publications

References 9 publications

Pentafluorobenzaldehyde and its utilizing in organic synthesis

Pentafluorobenzaldehyde and its utilizing in organic synthesis

Highly enantioselective epoxidation of styrenes: Implication of an electronic effect on the competition between spiro and planar transition states

Asymmetric Catalytic Routes to Dialkyl Peroxides and Oxaziridines

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