l-Amino Acid Based Urea鈥揟ertiary Amine-Catalyzed Chemoselective and Asymmetric Stereoablative Carboxylation of 3-Bromooxindoles with Malonic Acid Half Thioesters
An l-amino acid based urea鈥搕ertiary amine-catalyzed enantioselective stereoablative carboxylation of 3-bromooxindoles with malonic acid half thioesters (MAHTs) and diverse commercially available carboxylic acids has been developed. A series of valuable 3-substituted 3-hydroxy-2-oxindoles were obtained in high enantioselectivities (up to 93% ee). This chemoselective reaction represents the first example of MAHTs as carboxylating agents.