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 react ion of (eta(5)-C5H5)Re(CO)(3) with n-BuLi in THF at -78 degrees C reac ted with additional (eta(5)-C5H5)Re(CO)(3) to produce the dirhenium ac yl anion )-C5H5)(CO)(2)Re(C=O)[(eta(5)-C5H4)Re(CO)(3)]-Li+. Protonatio n of this acyl anion gave the dirhenium hydroxycarbene complex a(5)-C5 H5)(CO)(2)Re=C(OH)[(eta(5)-C5H4)Re(CO)(3)], while methylation gave the methoxycarbene complex 5)-C5H5)(CO)(2)Re=C(OCH3)[(eta(5)-C5H4)Re(CO)( 3)], which was characterized by X-ray crystallography. The methoxycarb ene complex reacted with n-BuLi to produce the butylcarbene complex (C O)(2)Re=C(CH2CH2CH2CH3)[(eta(5)-C5H4)Re(CO)(3)].