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.
Enantioselective Steglich Rearrangement of Oxindole Derivatives by Easily Accessible Chiral <i>N</i>,<i>N</i>-4-(Dimethylamino)pyridine Derivatives
作者:Hiroki Mandai、Takuma Fujiwara、Katsuaki Noda、Kazuki Fujii、Koichi Mitsudo、Toshinobu Korenaga、Seiji Suga
DOI:10.1021/acs.orglett.5b02089
日期:2015.9.18
Chiral N,N-4-(dimethylamino)pyridine (DMAP) derivatives, which can be readily prepared by the Ugi multicomponent reaction in a one-pot manner, have been efficiently applied to the enantioselective Steglich rearrangement of oxindole derivatives to give the desired products bearing a quaternary carbon center in high yield (>98% yield) and with high enantioselectivity (up to 99:1 er).