Enantioselective Synthesis of Axially Chiral Hydroxy Carboxylic Acid Derivatives by Rhodium-Catalyzed [2 + 2 + 2] Cycloaddition

Axially chiral hydroxy carboxylic acid derivatives were successfully synthesized with high yields and ee values by the cationic rhodium(I)/axially chiral biaryl bisphosphine complex-catalyzed enantioselective [2 + 2 + 2] cycloaddition. Axially chiral hydroxy and dihydroxy carboxylic acid derivatives, bearing the aryl group at the ortho-position of the alkoxycarbonyl group, were also synthesized with high regio- and enantioselectivity.