A formal (3 + 2) annulation–Cannizzaro cascade of bifunctional peroxides for the synthesis of dihydrofurans

Abstract

A complicated Michael addition–epoxidation–cyclization–Cannizzaro cascade of 2-formylallyl peroxides and β-keto esters has been developed under mild KOH basic conditions, which produces a pair of 2,2-bis(hydroxymethyl) and 2-carboxyl-2-hydroxymethyl dihydrofurans in good total yields. By switching to K₂CO₃ basic conditions, the reaction alternatively provides formyl epoxides in good yields via a Michael addition–epoxidation cascade. Detailed mechanistic investigations and the synthetic utility of the obtained products are also demonstrated.