A new approach to annelated butenolides. The total synthesis of (+/-)-isodrimenin

Article abstract of DOI:10.1002/recl.19871060906

A new approach to annelated butenolides has been developed starting from trans-5,5,8a-trimethyl-3,4,4a,5,6,7,8,8a-octahydro-1(2H)-naphthalenone (3) and cyclohexanones.A reaction sequence consisting of formylation of the enolates of these ketones, protection of the formyl group as its dioxolane and addition of methoxy(phenylthio)methyllithium has been used to introduce the necessary functionalized carbon atoms.Rearrangement of the adduct to α-(phenylthio)aldehydes, followed by hydrolysis of the dioxolane, resulted in the formation of butenolides.The method has been demonstrated in the total synthesis of (+/-)-isodrimenin.Direct hydrolysis of the adducts, obtained after addition of methoxy(phenylthio)methyllithium, followed by treatment with acid, also gave butenolides.