Asymmetric synthesis of homochiral differentially protected bis-β-amino acid scaffolds

Abstract

A strategy for the asymmetric synthesis of homochiral [( R, R)- or ( S, S)-], or meso-( R, S) bis-β-amino acid scaffolds, formally resulting from the stepwise conjugate addition of two differentially protected homochiral lithium amides to two α,β-unsaturated esters attached to a central arene, is demonstrated. Further manipulation enables the efficient synthesis of orthogonally protected pseudo- meso or pseudo- C 2 symmetric scaffolds via selective N-benzyl or N-allyl deprotection, enabling regio-, stereo- and chemoselective functionalisation.