Synthesis of α-Methylene β-Lactones, Novel Heterocycles

Article abstract of DOI:10.1021/jo00020a016

Triphenylphosphin deoxygenation of β-alkyl-, β,β-dialkyl-, and β,β-spirocycloalkyl-substituted α-methylene-β-peroxy lactones 3a-k, which are readily available by photooxygenation of the corresponding α,β-unsaturated carboxylic acids 1, and cyclization of the resulting α-methylene-β-hydroperoxy acids 2 constitute a convenient method for the preparation of a variety of α-methylene β-lactones 5.Alternatively, the α-methylene-β-hydroxycarboxylic acids 4 can be directly cyclized by benzenesulfonyl chloride in pyridine into these novel four membered ring heterocycles 5.