Creation of bispiro[pyrazolone-3,3′-oxindoles] via a phosphine-catalyzed enantioselective [3 + 2] annulation of the Morita–Baylis–Hillman carbonates with pyrazoloneyldiene oxindoles

Abstract

A [3 + 2] annulation between the Morita–Baylis–Hillman (MBH) carbonates and pyrazoloneyldiene oxindoles catalyzed by (S)-SITCP has been developed. Structurally novel bispiro[pyrazolone-3,3′-oxindoles] containing two contiguous quaternary stereogenic centers were created in excellent yields, in a diastereospecific and highly enantioselective manner.