Synthesis of new cardanol derivatives through combined iodination/palladium-catalysed cross-coupling reactions

A versatile approach to the synthesis of new cardanol derivatives through a combination of aromatic iodination of 3-n-pentadecylphenol and palladium-catalysed cross-coupling reactions has been developed. The extent of aromatic iodination is controlled by stoichiometry and affords either the mono-, di- or tri-iodo-cardanol derivatives. Suzuki, Heck and Sonogashira protocols were successfully applied for the vinylation, arylation and alkynylation of the iodo-cardanols. 2,4-Diiodo-5-n-pentadecylphenol underwent an unusual sequential regioselective dehalogenation/vinylation reaction. Sequential alkynylation/cyclisation of 2-iodo-3-n-pentadecylphenol derivatives were also investigated.