Synthesis of the Chiral Fragrance Methyl Chamomile by Asymmetric Hydrogenation

Abstract

An alternative synthesis of enantiomerically enriched 2-methylpentanoic butyl ester (Methyl Chamomile) is proposed. The process entails three different steps: the key one is the asymmetric hydrogenation of 2-methylenpentanoic acid catalysed by a Ru(II) complex and a chiral diphosphine