Dicarboxylic acid esters from the carbonylation of unsaturated esters under mild conditions

The methoxycarbonylation of unsaturated acids or esters catalysed by Pd complexes of bis(ditertiarybutyl-phosphinomethyl)benzene (DTBPMB) produces α,ω-diesters with selectivities >95%, even if the double bond is deep in the chain or conjugated to the carbonyl group; unsymmetrical esters can also be produced with high selectivity.