Reagent control in the aldol addition reaction of chiral boron enolates with chiral aldehydes. Total synthesis of (3S,4S)-statine

Boron enolates bearing menthone-derived chiral ligands are capable of fair to excellent diastereocontrol in their reactions with chiral aldehydes. Thioester-derived (better than ketone derived) enolates are able to control aldol stereochemistry irrespective of the aldehyde preferences. With thioacetate-derived chiral enolates and enantiopure N,N-dibenzyl alpha-amino aldehydes, either the 3,4-anti or the 3,4-syn aldol adduct can be obtained with very high diastereoselectivity just by changing the chiral boron ligand configuration. The above procedure was used for a stereoselective total synthesis of (3S, 4S)-statine. (C) 1997 Elsevier Science Ltd.