Asymmetric allylboration of α,β-enals as a surrogate for the enantioselective synthesis of allylic amines and α-amino acids

Optically pure allylic amines have been synthesized from alpha,beta-unsaturated aldehydes via allylboration with (-)-B-allyldiisopinocampheylborane, followed by Overman rearrangement. By incorporating crotyl and alkoxyallylboration, functionalization at delta-position was readily accomplished. By applying this methodology, the synthesis of several chiral a.-amino acids has been achieved.