Kinetic Resolution of Secondary Alcohols by the Combination of a Chiral Brønsted Acid, DABCO, and Acetyl Chloride
作者:Hiroki Mandai、Kyouta Murota、Koichi Mitsudo、Seiji Suga
DOI:10.1021/ol301373x
日期:2012.7.6
An efficient and simple protocol for the kineticresolution of secondary alcohols is presented. The new system is based on a combination of chiral Brønsted acid, DABCO, and acetyl chloride and gives various enantioenriched alcohols with selectivityfactors up to 105.
The kinetic resolution of secondary alcohols was examined by new chiral DMAP derivatives, which can readily be prepared by the Ugi multicomponent reaction in a one-pot operation. The initial screening of DMAP derivatives indicated that the catalyst bearing L-valine with an S configuration at the a-position of amide showed the best stereoselectivity factor. After the reaction conditions were optimized with (S,S)-4a in the kinetic resolution of secondary alcohols, various acyclic and cyclic secondary alcohols could be resolved with an s-factor of up to 12.