NOUVEAU MODE DE CYCLYSATION DE CETO-YLURES. APPLICATION A UNE SYNTHESE IGINALE D'ACYL-3 HYDROXY-4-COUMARINES ET DE L'HYDROXY-11 BENZO-(b) 12 XANTHONE-12

Article abstract of DOI:10.1016/S0040-4020(01)92042-3

The thermal decomposition of keto-ylides resulting from the reaction of m- and p-acetoxy benzoyl chlorides with Ph3P=CH-COOMe leads, after saponification to m- and p-phenylpropiolic acid respectively.Ortho substitution by an acyl group generally changes the orientation of the reaction.Thus o-acetoxy-, benzoyloxy- or phenylacetoxy benzoyl chlorides respectively afford: <*> and <*> (R=Me,Ph) in satisfactory yields.Saponification of the first and second ones gives:<*> (R=Me, Ph).This constitutes a new, convenient route to 3-acyl 4-hydroxy cumarins and 11-hydroxy 12H-benzoxanthene 12-one.Formation of these last products involves the carbonyl of the acyloxy-substituent and not of the acyl chloride as previously observed in these series.