One step synthesis of γ-alkylidenebutenolides from simple vinyl carboxylic acids and alkenes

The first tandem cross-coupling/oxa-Michael addition/dehydrogenation process via rhodium chemistry is described, which provides a straightforward and atom-economical protocol for the synthesis of a wide range of valuable gamma-alkylidenebutenolides. This method is of particular interest because of employing widely available and low cost vinyl carboxylic acids and electron-deficient alkenes as building blocks. Moreover, the methodology can be applied to a gram scale synthesis with 1 mol% catalyst loading.