A simple and highly efficient procedure for construction of quaternary carbons centers by tributylphosphine catalyzed bis-Michael addition

The tributylphosphine-catalyzed bis-Michael addition reaction of various kinds of α,β-unsaturated carbonyl compounds with active methylenes is described. This is a convenient and rapid method for generating quaternary carbons centers and useful procedure for the synthesis of branched core and highly substituted trans cyclohexanones. All the reactions were completed in 60 min and afford the corresponding products in excellent yields.