Highly Enantioselective Epoxidation of <i>cis</i>-Olefins by Chiral Dioxirane

Tian, Hongqi; She, Xuegong; Shu, Lianhe; Yu, and Hongwu; Shi, Yian

doi:10.1021/ja003049d

Cited by 135 publications

(70 citation statements)

References 15 publications

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“…The Katsuki-Jacobsen epoxidation, which is catalyzed by chiral Mn(III)-salen with NaOCl/PhIO as an oxidant, achieves good yields and high stereoselectivities (84-94% ee) for the epoxidation of cis-alkenes [21]. The Shi epoxidation, which is catalyzed by the fructose-derived ketone and oxone, has been successfully used in the epoxidation of trans-alkenes, yielding the corresponding oxides with 93-98% ee [74]. However, for nonfunctionalized terminal aliphatic alkenes, chemocatalysts typically display low stereoselectivity [7].…”

Section: Asymmetric Epoxidation Of Aliphatic Alkenesmentioning

confidence: 99%

Biocatalytic Epoxidation for Green Synthesis

Lin

Liu

et al. 2016

Green Biocatalysis

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Section: Asymmetric Epoxidation Of Aliphatic Alkenesmentioning

confidence: 99%

Biocatalytic Epoxidation for Green Synthesis

Lin

Liu

et al. 2016

Green Biocatalysis

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“…Computations by Bach et al iii and Houk et al iva have shown the epoxidation of olefins by dioxiranes to proceed through a “spiro” transition state as shown in Figure 1a. Although planar transition state structures (Figure 1b) are invoked by Shi and Bartlett in some cases, ix,x computational evidence continues to support a spiro transition stateiiia or hybrid planar-spiro transition state in more complex systems, as shown by Singleton vb…”

Section: Introductionmentioning

confidence: 99%

Quantitative DFT Modeling of the Enantiomeric Excess for Dioxirane-Catalyzed Epoxidations

et al. 2009

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Herein we report the first fully quantum mechanical study of enantioselectivity for a large dataset. We show that transition state modeling at the UB3LYP-DFT/6-31G* level of theory can accurately model enantioselectivity for various dioxirane-catalyzed asymmetric epoxidations. All the synthetically useful high selectivities are successfully "predicted" by this method. Our results hint at the utility of this method to further model other asymmetric reactions and facilitate the discovery process for the experimental organic chemist. Our work suggests the possibility of using computational methods not simply to explain organic phenomena, but also to predict them quantitatively.

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“…[52][53][54]. Chiral dioxiranes were shown recently to be effective for asymmetric epoxidation of trans-, trisubstituted , and certain cis-alkenes (92)(93)(94)(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)(94)(95).…”

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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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Highly Enantioselective Epoxidation of cis-Olefins by Chiral Dioxirane

Cited by 135 publications

References 15 publications

Biocatalytic Epoxidation for Green Synthesis

Biocatalytic Epoxidation for Green Synthesis

Quantitative DFT Modeling of the Enantiomeric Excess for Dioxirane-Catalyzed Epoxidations

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

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