Development of Biligands Magnesium Catalysis in Asymmetric Conjugate Reactions of C3-Pyrrolyl-Oxindoles.

A magnesium catalyzed asymmetric conjugate reaction of C3-pyrrolyl-oxindoles with terminal alkynones is presented. The current asymmetric conjugate reaction relies on the development of novel combinational magnesium catalysis involving two chiral ligands. The current protocol proceeds smoothly and gives the corresponding enantioenriched 3,3-disubstituted oxindole skeletons with good enantioselectivities. Furthermore, the conjugate adducts could be transferred to spiro oxindole structures containing an eight-membered ring in high ee values.