Tandem Cyclization–Michael Reaction by Combination of Metal- and Organocatalysis

The use of a catalytic amount of platinum complexes (1 mol %) was found to be compatible with different organocatalysts (DABCO or the Jørgensen–Hayashi catalyst) that were used in the functionalization of various activated methylenes. By this method, a series of lactones with C-3 quaternary centers and substitution at C-5 were prepared.