Visible Light-Induced Trifluoromethylation and Perfluoroalkylation of Cysteine Residues in Batch and Continuous Flow

We report a visible light-induced trifluoromethylation and perfluoroalkylation for cysteine conjugation using Ru(bpy)3(2+) as photocatalyst and inexpensive RFI as coupling partner. The protocol allows the introduction of a variety of perfluoro alkyl groups (C1-C10) and a CF2COOEt moiety. The reaction is high yielding (56-94% yield) and fast (2 h in batch, 12 examples). Process intensification in a photomicroreactor accelerated the reaction (5 min reaction time) and increased the yields (8 examples). Quantum yield investigations support a radical chain mechanism.