Asymmetric aldol reaction of isatins with acetone in the presence of terpene amino alcohols

Asymmetric aldol reactions of isatin and 4,6-dibromoisatin with acetone are efficiently catalyzed by β-amino alcohols derived from α-pinene and 3-carene. The target compounds can be isolated by crystallization from toluene, which eliminates the need for using chromatography and makes the asymmetric synthesis of (R)-convolutamydine A (up to 94% ee and yield 75%) simple and convenient.