Synthesis of β,γ,γ -Tri- or γ,γ -Disubstituted α -Methylene-γ -butyrolactones Starting from the Baylis-Hillman Adducts

A number of -methylene-『butyrolactones display signi ficant biological activity, and many syntheses of this class of molecules have been described?-3Especially -methylene-Ybutyrolactones having carboxylic acid or ester group are the basic skeletons of a number of biologically active compounds, which showed antitumor antibiotic, antibacterial, antifungal and growth regulating effects?Roy and co workers have published the synthesis of methylenolactocin,