Conversion of an Acetylide−Silylene Complex to an Alkenylcarbyne Complex by Consecutive Ketone Addition and Base-Induced Silanone Elimination

A new acetylide−silylene complex, Cp*(CO)2W(SiPh2)(CCSiMe3) (4), was synthesized by the reaction of Cp*(CO)2W(NCMe)Me with Ph2HSiCCSiMe3. Complex 4 reacted with acetone to give the six-membered cyclic vinylidene complex Cp*(CO)2 WCC(SiMe3)CMe2OSiPh2 (5) by acetone insertion into the acetylide−silylene framework. Treatment of 5 with 4-(dimethylamino)pyridine resulted in the formation of the alkenylcarbyne complex Cp*(CO)2WCC(CMe2)SiMe3 (8) and cyclic diphenylsiloxanes.