Synthesis of <i>gem</i>-Difluoromethylenated Bicyclo[<i>m.n.</i>0]alkan-1-ols and Their Ring-Expansion to <i>gem</i>-Difluoromethylenated Macrocyclic Lactones

Fluoride-catalyzed stereoselective nucleophilic addition of PhSCF₂SiMe₃ (<b>1</b>) to α-carboethoxycycloalkanones <b>2</b> followed by intramolecular radical cyclization of the resulting <i>cis</i>-<b>3</b> adduct afforded the corresponding <i>gem</i>-difluoromethylenated bicyclic compounds <b>4</b>, which underwent ring-expansion followed by the Baeyer–Villiger-type oxidation of the resulting macrocyclic ketone intermediates to give <i>gem</i>-difluoromethylenated macrocyclic lactones <b>5</b>