Divergent Synthesis of Tetrafluoroethylene-Containing Tetrahydrofuran (THF) and Dihydropyran (DHP) Derivatives

A divergent synthetic methodology for tetrafluoroethylene (CF2CF2)-containing tetrahydrofurans (THFs) and dihydropyrans (DHPs), employing 4-bromo-2,2,3,3-tetrafluoro-4-penten-1-ol derivatives as common synthetic intermediates, has been developed. Mechanistic studies indicate that the reaction proceeds chemoselectively, either via copper-catalyzed Ullmann-type intramolecular O-vinylation or through tandem CF2CF2 group-promoted β-elimination followed by 6-endo-dig cycloisomerization. Further investigations demonstrate that both cyclic ethers can be diastereoselectively transformed into a wide range of CF2CF2-containing C-glycoside derivatives.