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)₂W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.