Chiral ligands derived from Abrine. 1. Synthesis of sec- and tert-β-amino alcohols and catalysis for enantioselective addition of diethylzinc toward aromatic aldehydes

Abstract

A number of indole-containing chiral beta-amino alcohols 3a-d and 9a-e have been synthesized from the alkaloid, Abrine (1) readily available from seeds of Abrus precatorius collected in Yunnan Province of China Catalysis of the synthesized chiral ligands 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 uncovered. Enantiomeric excess of the product up to 94.2% was recorded.