Selective synthesis of α-methylenyl zirconacyclopentene via cross-coupling of alkyne and allene

α-Methylenyl zirconacyclopentenes are synthesized regio- and stereoselectively via reductive intermolecular cross-coupling of alkynes and allenes promoted by zirconocene species ‘Cp₂Zr’. An interesting reductive intramolecular coupling of the α-methylenyl zirconacyclopentene has been observed in the presence of DMAD/CuCl, resulting in the generation of cyclobutene with an exocyclic double bond. Polysubstituted 1,4-dienes can be given with high selectivity and good yields.