Asymmetric Epoxidation of 1,1-Disubstituted Terminal Olefins by Chiral Dioxirane via a Planar-like Transition State
作者:Bin Wang、O. Andrea Wong、Mei-Xin Zhao、Yian Shi
DOI:10.1021/jo801576k
日期:2008.12.19
Various 1,1-disubstituted terminalolefins have been investigated for asymmetric epoxidation using chiral ketone catalysts. Up to 88% ee has been achieved with a lactam ketone, and a planar transition state is likely to be a major reaction pathway.
applicability. Herein, we report an efficient PPh3-promoted metal-free strategy for deoxygenation of epoxides to generate alkene derivatives. The success of deoxyalkenylation of epoxides bearing a wide range of functional groups to give terminal, 1,1-disubstituted, and 1,2-disubstituted alkenes manifests the powerfulness and versatility of this strategy. Moreover, gram-scale synthesis with excellent yield and