Pt-catalyzed sp3 C-H bond activation of o-alkyl substituted aromatic carboxylic acid derivatives for the formation of aryl lactones

Synthesis of aryl lactones from ortho-alkyl substituted aromatic carboxylic acids is described on the basis of sp(3) C-H bond activation using either palladium or platinum catalysts. Kinetic isotope studies reveal that the reaction takes place presumably by the chelation assistance of metal catalyst to the carboxylic group followed by the C-H bond activation. (c) 2006 Elsevier Ltd. All rights reserved.