Formation of a dirhenium carbene complex from reaction of (eta(5)-C5H4Li)Re(CO)(3) with (eta 5-C5H5)Re(CO)(3)

The ring-metalated complex (eta(5)-C5H4Li)Re(CO)(3) generated by reaction of (eta(5)-C5H5)Re(CO)(3) with n-BuLi in THF at -78 degrees C reacted with additional (eta(5)-C5H5)Re(CO)(3) to produce the dirhenium acyl anion (eta(5)-C5H5)(CO)(2)Re(C=O)[(eta(5)-C5H4)Re(CO)(3)]-Li+. Protonation of this acyl anion gave the dirhenium hydroxycarbene complex (eta(5)-C5H5)(CO)(2)Re=C(OH)[(eta(5)-C5H4)Re(CO)(3)], while methylation gave the methoxycarbene complex (eta(5)-C5H5)(CO)(2)Re=C(OCH3)[(eta(5)-C5H4)Re(CO)(3)], which was characterized by X-ray crystallography. The methoxycarbene complex reacted with n-BuLi to produce the butylcarbene complex (eta(5)-C5H5)(CO)(2)Re=C(CH2CH2CH2CH3)[(eta(5)-C5H4)Re(CO)(3)].