Manganese(III) γ-Lactone Annulation with Substituted Acids

Article abstract of DOI:10.1021/jo00217a025

Manganese(III) acetate oxidation of several HOOCCH2X, X = electron withdrawing group, in the presence of alkenes led to the formation of α-substituted γ-lactones.Chloroacetic acid gave α-chloro-γ-lactones, which were converted in two steps to the corresponding α,β-unsaturated γ-lactones. 3-Chloropropanoic acid led to the α-methylene γ-lactone after base induced elimination of HCl.Cyanoacetic acid produced α-cyano γ-lactones which could be hydrolytically decyanated or converted to the α-methylene γ-lactones in two steps.Potassium methyl malonate was oxidized and annulated onto alkenes to give α-carbomethoxy γ-lactones in reasonable yields.The method demonstrates a general route into several useful types substituted γ-lactones.