Recyclable Trifluoromethylation Reagents from Fluoroform

We present a strategy to rationally prepare CF3– transfer reagents at ambient temperature from HCF3. We demonstrate that a highly reactive CF3– adduct can be synthesized from alkali metal hydride, HCF3, and borazine Lewis acids in quantitative yield at room temperature. These nucleophilic reagents transfer CF3– to substrates without additional chemical activation, and after CF3 transfer, the free borazine is quantitatively regenerated. These features enable syntheses of popular nucleophilic, radical, and electrophilic trifluoromethylation reagents with complete recycling of the borazine Lewis acid.