AN EXCEPTION TO THE GENERAL MECHANISM OF CO INSERTION INTO THE ALKYL-MANGANESE BOND

Two-electron donor ligands L enter trans (and not cis as in other manganese examples) to the acyl group in the reaction of fac-[Mn(CO)3(bipy)(Me)] 1 with L to give cis,trans-[Mn(CO)2(L)(bipy)(COMe)] 2; the reaction of 1 with *CO (CO 99% enriched in C-13) gives cis,trans-[Mn(CO)2(*CO)(bipy)(COMe)] 4, ruling out the formation of the possible intermediate cis,cis-[Mn(CO)2(L)(bipy)(COMe)] 3.