Chiral ligands derived from Abrine .2. Oxazolidines as promoters for enantioselective addition of diethylzinc toward aromatic aldehydes

A number of indole-containing chiral oxazolidines 2a-i have been synthesized from Abrine readily available from the seeds of Abrus precatorius. Catalysis of these oxazolidines for the addition of diethylzinc toward benzaldehyde was examined. A significant role of the substituent(s) in the catalyst on the degree of asymmetric induction was noted. Moderate enantioselectivity up to 59.8% was recorded. Copyright (C) 1996 Published by Elsevier Science Ltd