Enantioselective three-component synthesis of 4-arylated dehydroprolines: [3+2] annulation of allenylstannane and α-imino ester

An enantioselective [3+2] annulation reaction of allenylstannane and α-imino ester was developed. Stille coupling of the resulting 4-stannyl dehydroproline gave optically active 4-arylated dehydroprolines in good yields.