Visible-Light-Induced\nMarkovnikov Hydroalkoxylation\nof α‑Trifluoromethyl Alkenes with <i>ortho</i>-Diketones

We report, for the first time, a visible-light-promoted\nMarkovnikov\nhydroalkoxylation of α-trifluoromethyl alkenes with 1,2-diketones.\nThis transformation proceeded smoothly in the presence of a tertiary\namine (Et<sub>3</sub>N), providing a series of enol ethers containing\nthe trifluoromethylated tetrasubstituted center in moderate to excellent\nyields. In this protocol, hydrogen atom transfer between this amine\nand 1,2-diketone substrate affords a ketyl radical and an α-aminoalkyl\nradical, which engages in the formation of a radical anion of the\nα-CF<sub>3</sub> alkene via a single electron transfer. Notably,\nthis protocol features several advantages including metal- and external\nphotocatalyst-free, mild conditions, easy operation, a broad substrate\nscope, and good functional group tolerance. Moreover, by applying\nthis new method, a great number of important deuterium-labeled organofluorine\ncompounds can be readily prepared using CD<sub>3</sub>OD as a deuterium\nsource.