Direct Hydrodefluorination of CF 3 -Alkenes via a Mild S N 2' Process Using Rongalite as a Masked Proton Reagent.

A concise and efficient hydrodefluorination process was developed for the synthesis of gem -difluoroalkenes. This reaction employs rongalite as a masked proton source and does not require any additional catalysts or reductants. Notably, trifluoromethyl alkenes having both terminal and internal double bonds are compatible with this process, allowing for a wider range of substrates. The successful late-stage functionalizations of pharmaceuticals and gram-scale syntheses were used to demonstrate the viability of this method.