Improved synthesis of 8-oxabicyclo[3.2.1]octanes via tandem C–H oxidation/oxa-[3,3] Cope rearrangement/aldol cyclization

A tandem C–H oxidation/oxa-[3,3] Cope rearrangement/aldol reaction of allylic silylethers promoted by T+BF4−(tempo oxoammonium tetrafluoroborate)/ZnBr2 has been successfully developed allowing the efficient construction of 8-oxabicyclo[3.2.1]octanes and their analogs with a wide substrate scope.