Michael addition of ortho-lithiated aryloxiranes to alpha,beta-unsaturated malonates: synthesis of tetrahydroindenofuranones

A short and efficient synthesis of tetrahydroindenofuranones based on the Michael addition of ortho-lithiated aryloxiranes to alkylidene malonates followed by the nucleophilic oxirane ring-opening and subsequent lactonization is described. The methodology has been applied to the synthesis of a structural analogue of epipodophyllotoxins.