Diastereoselective synthesis of chiral non-racemic 2-substituted 2-boranatophosphino ethanoic acid: a potential intermediate to chiral ligands for asymmetric catalysis

Abstract

Chiral α-amidophosphine boranes 7a– b can be diastereoselectively alkylated, using a phenylglycinol derivative as a chiral inducer, to furnish α-substituted α-amidophosphine boranes 8– 12 with up to 99% diastereoisomeric excess. Selective reduction of the amidophosphine boranes afforded optically pure β-boranatophosphine-alcohol 13. The latter one can then be oxidized in boronatophosphine acid 14.