New indane derived aminoalcohols as chiral ligands for the catalytic enantioselective addition of diethylzinc to aldehydes

Abstract

Secondary amines react with (1 R,2 S)-indene oxide 1 in a completely regioselective manner leading to trans-2-dialkylamino-1-indanols 4a— d in high yield. A Mitsunobu inversion via the corresponding p-nitrobenzoates, followed by reduction with DIBALH leads to the cis-2-dialkylamino-1-indanols 5a— d also in high yield. These two new classes of aminoindanols have been tested as chiral ligands for the enantioselective addition of diethylzinc to both aliphatic and aromatic aldehydes, leading to 1-substituted 1-propanols with up to 80% e.e. A very simple procedure for the enantiomeric enrichment of 1 from 88% to ≥99% e.e. is also reported.