Transformation of a hydroxyl into an acyl group on α-pyrone ring: a novel route to 3,4-diacylcoumarins

The transformation of a hydroxyl into an acyl group, a transformation which has been extensively investigated on the benzene nucleus of several substrates, is now applied successfully for the first time to a heterocyclic ring and specifically to the pyrone ring of coumarin to yield novel 3,4-diacylcoumarins in good yields. The reaction involves formation of a new C-C bond. (C) 2011 Elsevier Ltd. All rights reserved.