Heterogeneous asymmetric aminohydroxylation of alkenes using a silica gel-supported bis-cinchona alkaloid

Abstract

Excellent enantioselectivities of up to > 99% ee have been achieved in the heterogeneous asymmetric aminohydroxylation of trans-cinnamate derivatives using silica gel-supported (QN)(2)PHAL [SGS-(QN)(2)PHAL 1]; the dark brown 1.0s complex, recovered by simple filtration after reaction, could be reused without any loss of enantioselectivity.