%0 Journal Article
%T Enantioselective Synthesis of 2,2-Disubstituted Terminal Epoxides via Catalytic Asymmetric Corey-Chaykovsky Epoxidation of Ketones
%A Toshihiko Sone
%A Akitake Yamaguchi
%A Shigeki Matsunaga
%A Masakatsu Shibasaki
%J Molecules
%D 2012
%I MDPI AG
%R 10.3390/molecules17021617
%X Catalytic asymmetric Corey-Chaykovsky epoxidation of various ketones with dimethyloxosulfonium methylide using a heterobimetallic La-Li3-BINOL complex (LLB) is described. The reaction proceeded smoothly at room temperature in the presence of achiral phosphine oxide additives, and 2,2-disubstituted terminal epoxides were obtained in high enantioselectivity (97%¨C91% ee) and yield ( > 99%¨C88%) from a broad range of methyl ketones with 1¨C5 mol% catalyst loading. Enantioselectivity was strongly dependent on the steric hindrance, and other ketones, such as ethyl ketones and propyl ketones resulted in slightly lower enantioselectivity (88%¨C67% ee).
%K asymmetric catalysis
%K asymmetric synthesis
%K epoxide
%K rare earth metal
%K sulfur ylide
%U http://www.mdpi.com/1420-3049/17/2/1617