Simple phosphinite–oxazoline ligands for asymmetric catalysis

Abstract

4-(Hydroxymethyl)oxazolines, derived from ( S)-serine methyl ester and a variety of acid chlorides (RCOCl), were reacted with Ph 2PCl to give new phosphinite–oxazoline P–N ligands. These mediate the palladium catalysed asymmetric alkylation with dimethyl malonate with the following racemic propenyl substrates R 1CHCHCH(OX)R 1: (a) R 1=Ph, X=Ac—96% e.e.( S) with R=Ph; (b) R 1=Me, X=CO 2 t Bu—70% e.e.( S) with R=(η 5-C 5H 4)(η 4-C 4Ph 4)Co.