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- ...