Two types of chiral Brønsted acid catalysts have been shown to catalyze regio- and enantioselective nitroso aldol synthesis between nitrosobenzene and achiral enamine. The combination of Brønsted acidity and amine moiety of enamine realizes complete regioselectivity with high enantioselectivity. After a survey of Brønsted acid catalysts, 1-naphthyl glycolic acid is found to be optimal in the O-nitroso aldol pathway, while 1-naphthyl TADDOL is the best catalyst for the N-nitroso aldol pathway. This is based on our finding on the control of regioselectivity by changing the amine moiety of enamine and the choice of Brønsted acidity.
ASJC Scopus subject areas
- Colloid and Surface Chemistry