Manganese(III)-Mediated Spirodilactonization

Article abstract of DOI:10.1021/jo00207a024

Manganese(III) oxidation of malonic acid in the presence of alkenes results in the formation of spiro-fused lactones, 2,7-dioxaspiro<4.4>nonane-1,6-diones.Terminal alkenes produce a mixture of the three possible diastereomers.The stereochemistry of the diastereomeric spirodilactones was determined by NMR and corroborated by the intensity of the coupled IR carbonyl stretching frequencies. 1,1,6,6-Tetrasubstituted 1,5-hexadienes give in one step tricyclic dilactones.Mechanistic and synthetic aspects of this reaction are discussed.