Constructing chiral aza-quaternary carbon centers by enantioselective carbonylative Heck reaction of o-iodoanilines with allenes

The construction of chiral aza-quaternary carbon centers via C–N bond formation has been achieved by a palladium-catalyzed asymmetric carbonylative Heck reaction of o-iodoanilines with allenes, providing chiral dihydroquinolinone derivatives with moderate to high yield and enantiomeric ratio (er). The er could be improved to 99/1 through the recrystallization of the isolated products. Adding o-iodoaniline into the reaction by syringe pump was crucial to diminish the side reactions of reactive o-iodoanilines and improve the chemoselectivity. Utilizing the chirality induction of an assembled aza-quaternary stereogenic center, molecules bearing vicinal chiral quaternary carbon centers or multiple chiral centers can be rapidly prepared.