Macrocyclic Lactone Formation through Sulfide Contraction. Synthesis of (+/-)-Diplodialide A

Article abstract of DOI:10.1021/jo01298a022

A methodology for the synthesis of macrocyclic β-keto-lactones from ω-hydroxy thioamides is described.The hydroxy thioamides were esterified with chloroacetyl chloride, and the resulting chloro esters underwent Eschenmoser sulfide contraction when treated with sodium iodide, diisopropylethylamine, and triethyl phosphite in acetonitrile.The β-keto lactones were obtained in 25-58 percent yield.The utility of the method was demonstrated by synthesis of diplodialide A.