An Efficient Route to Access Spirooxindole–Pyrazolone-Fused Cyclopentenes by a Diastereoselective [3+2] Annulation

Abstract

A DMAP-catalyzed, highly diastereoselective, [3+2] cycloaddition of pyrazolone-derived Morita–Baylis–Hillman carbonates to 3-methyleneoxindoles has been developed. A variety of structurally diverse and complex spiropyrazolone-fused oxindoles bearing three contiguous chiral centers have been synthesized in high yields (up to 98%) and with excellent diastereoselectivities (up to 99:1). Moreover, the synthetic potential of this protocol has been demonstrated by performing a Suzuki coupling reaction.