Studies on the mechanism for stereoisomerization of 1-zirconacyclopent-3-yne compounds

► 2,5-Disubstituted 1-zirconacyclopent-3-yne compounds isomerized from trans to cis, and vice versa. ► A dinuclear complex of 1,4-bis(trimethylsilyl)butatriene was synthesized, although it was unimportant for the isomerization. ► The isomerization reaction was first order in zirconium species. ► Kinetic isotope effect (kH/kD = 1.8) was observed.