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

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