Diastereoselective Epoxidation of Cyclohexene Derivatives by Dioxiranes Generated in Situ. Importance of Steric and Field Effects
作者:Dan Yang、Guan-Sheng Jiao、Yiu-Chung Yip、Man-Kin Wong
DOI:10.1021/jo9821978
日期:1999.3.1
In this paper, diastereoselective epoxidation of substituted cyclohexenes (substrates 1-7) by dioxiranes generated in situ from ketones and Oxone was systematically investigated. The results revealed that the diastereoselectivity was determined by the steric and field effects of both dioxiranes and substrates, and high diastereoselectivity can be achieved by tuning the ketone structure. Among the ketones
A Novel Epoxidation Reaction of Olefins Using a Combination of Chloramine-M, Benzaldehyde, and Benzyltriethylammonium Chloride
作者:Dan Yang、Chi Zhang、Xue-Chao Wang
DOI:10.1021/ja993472q
日期:2000.5.1
products. Good to excellent diastereoselectivities were obtained for epoxidation of two substitutedcyclohexenes. Chloramine-T was found to give a slower reaction than Chloramine-M. cis-N-Sulfonyloxaziridine D is proposed to be the epoxidizing agent in this novel epoxidation reaction on the basis of the mechanistic studies.
Diastereoselective epoxidation of allylically substituted alkenes using metalloporphyrin catalysts
申请人:Che Chi-Ming
公开号:US20050209470A1
公开(公告)日:2005-09-22
Diastereoselective epoxidation of allylically substituted alkenes using metalloporphyrins as catalyst provides high trans-selectivities (i.e., trans-:cis-epoxide ratio). A diversity of cycloalkenes bearing different allylic substituents are shown to be efficiently epoxidized to afford the corresponding trans-epoxides with excellent trans-selectivities (up to >98%) and good yields (up to 99%). Acyclic allylic alkenes bearing different allylic substituents are efficiently epoxidized to afford the corresponding erythro-epoxides with good erythro-selectivities. The metalloporphyrin-catalyzed reactions exhibit up to 20 times higher trans-selectivities than the conventional method using m-chloroperoxybenzoic acid as oxidant.