ene-acetals to spontaneously generate 6α-hydroxy-bis-acetals that could serve as precursors for a Cannizzaro-type rearrangement, yielding bis-angularly substitutedcis-fusedlactones. Both the oxidizing reagent, m-CPBA or NaBO 3 , and the substitution pattern can be important in determining the course of the epoxidation/ring-opening sequence, with NaBO 3 being the ideal electrophilic oxidant for the