Improved carbonylation of heterocyclic chlorides and electronically challenging aryl bromides.

[reaction: see text] Optimized conditions are described that effect the carbonylation of diverse heterocyclic chlorides to yield the desired alkyl esters. In addition, bromoanilines and bromoanisoles, which normally are poor substrates under standard carbonylation protocols, were efficiently converted to the desired products under these new conditions. The nature of the metal bidentate ligand complex was found to be critical.