Tributylphosphine as a superior catalyst for the α-C-addition of 1,3-dicarbonyl compounds to electron-deficient alkynes

The present work describes an improved one pot access to α-(gem-difunctional) cinnamate esters and to conjugated 1,3-diketones exploiting the addition of 1,3-diketones, β-keto esters and malonates to alkynoates catalyzed by phosphines. Among the catalysts, nBu3P was found as one of the most effective allowing the reaction to proceed in milder conditions and in a more general manner than with other phosphines.