An unusual alkylidyne homologation.

The reaction of [W([triple bond, length as m-dash]CH)Br(CO)2(dcpe)] (dcpe = 1,2-bis(dicyclohexylphosphino)ethane) with tBuLi and SiCl4 affords the trichlorosilyl ligated neopentylidyne complex [W([triple bond, length as m-dash]CtBu)(SiCl3)(CO)2(dcpe)]. This slowly reacts with H2O to afford [W([triple bond, length as m-dash]CCH2tBu)Cl3(dcpe)] and ultimately H2C[double bond, length as m-dash]CHtBu via an unprecedented alkylidyne homologation in which coordinated CO is the source of the additional carbon atom with potential relevance to the Fischer-Tropsch process.