Process for preparing enriched enantiomers of 3-(Benzo[1,3]dioxol-5-yl)-2-methylpropanal

摘要

A process is described for preparing enriched enantiomers of the compound 3-(benzo[1,3]dioxol-5-yl)-2-methylpropanal of formula (I) comprising the following steps: i) reacting the racemic compound 3-(benzo[1,3]dioxol-5-yl)-2-methylpropanol (2) with phthalic anhydride to give the racemic acid (3); ii) resolving the racemic acid (3) with optically active 1-aryl-1-ethanamine (4) in which Ar is an aromatic or heteroaromatic group having from 6 to 12 members optionally substituted with one or more substituents chosen from the group consisting of (C 1 -C 3 ) alkyl, (C 1 -C 3 ) alkoxy and halogen; iii) recovering the (S)-(2) and (R)-(2) alcohols from the resolved acids (3) of step ii) by alkaline hydrolysis; iv) converting the (S)-2 and (R)-2 alcohols into the respective (S) and (R) enantiomers of compound (I).