Completely Stereocontrolled Aldol Reaction of Chiral β‑Amino Acids

Abstract

A general protocol to independently access stereoisomerically pure β′-hydroxy-β-amino acid derivatives that is based on dibutylboron triflate-mediated aldol reaction of suitably protected β-amino acids bearing chiral oxazolidinone auxiliary is reported. The method smoothly afforded <i>syn</i>-aldol (α,β′-<i>syn</i>) products in pure form and excellent isolated yield. Both α,β-<i>syn</i> and α,β-<i>anti</i> isomers are readily accessible solely through the choice of the oxazolidinone chirality. This method allows for the preparation of stereoisomeric β′-hydroxy-β-amino acid derivatives that were previously unreported