2,3,3,3-Tetrafluoropropene (HFO-1234yf) as a CF3-Building Block: Synthesis of Enol Ethers and Vinyl Sulfides

Abstract

2,3,3,3-Tetrafluoropropene (HFO-1234yf) is an inexpensive and readily available fluorinated building block, owing to its growing use as a low global warming potential 4th generation refrigerant, but there have so far been few reported uses of this fluoroalkene in organic synthesis. Herein, we report our investigations into nucleophilic substitution reactions of HFO-1234yf with alkoxide and thiolate derivatives. The regiochemistry of these transformations varies with conditions and we propose these reactions proceed through addition–elimination with reversible formation of a carbanion intermediate. The regioselectivity is dictated by hard/soft nucleophile/electrophile control. This is supported by deuterium trapping of the proposed reactive intermediate. The effect of solvent and base choice was examined and the substrate scope for the synthesis of α-trifluoromethyl enol ethers was expanded.