Toward Transition Metal-Catalyzed Carbonylation of Methanol without HI as Copromoter:  Catalytic Exocyclic Carbonylation of Cycloimino Esters

[reaction: see text] Initial studies of a rare exocyclic C-O bond carbonylation are reported. Under the catalysis of Co(2)(CO)(8) in the absence of HI as the copromoter, cycloimino esters are carbonylated to afford N-acyllactams in high yields under relatively mild conditions (100-160 degrees C and 200-1000 psi). The reaction is interesting because it opens up the possibility of carbonylation of alcohols in the absence of HI.