Diastereo- and enantio-selective crotylation of α-ketoesters using crotyl boronic acid ester complexes

A diastereo- and enantio-selective crotylation of ethyl pyruvate has been achieved using a chiral boronic acid auxiliary-based approach. This reaction creates two contiguous stereogenic centers, one of which is a quaternary carbon with complete diastereoselectivity and with enantioselectivities up to 7:1 (73% ee).