Palladium-Catalyzed Borylstannylative Carbocyclization of Diynes and an Enyne Compound

Abstract

Highly regio- and stereoselective borylstannylative carbocyclization of diynes 2a−f with the borylstannane 1 are efficiently catalyzed at room temperature by a series of palladium complexes such as Cl2Pd(PPh3)2, Cl2Pd[P(o-tolyl)3]2, Pd(PPh3)4, and Pd(dba)2, giving 1-(borylmethylidene)-2-(stannylmethylidene)cycloalkane derivatives 3a−f in high yields. A 1,6-enyne (2g) also reacts similarly to afford a high yield of the corresponding cyclized product 3g.