Synthesis of new chiral derivatives from (S)-indoline-2-carboxylic acid and their application to asymmetric reduction

Abstract

New chiral amino alcohols derived from (S)-indoline-2-carboxylic acid were used for reducing aceptophenone to optically active 1-phenylethanol, which were (S)-2-((diphenyl)hydroymethyl)indoline and (2S, 3aS, 7aS)-2-((diphenyl)hydroxymethyl)octahydroindole. The chiral oxazaborolidine prepared from borane and (s)-2-((diphenyl)hydroxymethyl)indoline reduced acetophenone to the optically active 1-phenylethanol (chemical yield 60 \%, optical yield 80.4\% e.e.). The chiral oxazaborolidine prepared from borane and (2S, 3aS, 7aS)-2-((diphenyl)hydroxymethyl) octahydroindole reduced acetophenone to the optically active 1-phenylethanol (chemical yield 50 \%, optical yield 70 \% e.e).