Chemoselective 1,3-dipolar cycloadditions of azomethine ylide with conjugated dienes

Methods are described of synthesizing various 3-carboxy-4-vinyl pyrrolidines, versatile building blocks for our drug discovery efforts. The 1,3-dipolar cycloaddition between activated olefins and nonstabilized azomethine ylide is a known method for synthesizing pyrrolidines in a stereospecific manner. Steric and electronic effects on the chemoselectivity of the 1,3-dipolar cycloaddition between azomethine ylide and α,β,γ,δ-unsaturated carboxylates have been explored.