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

Abstract

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