Photocatalytic\nGeneration of β‑Fluoroalkylated\nα‑Carbonyl Carbocations

Nucleophilic\naddition to α,β-unsaturated carbonyl compounds\nnormally occurs at the carbonyl carbon or β-carbon. The direct\nα-nucleophilic addition at the α-carbon can hardly be\nachieved due to electronic mismatch. In this work, we report the nucleophilic\naddition of β-fluoroalkyl α-carbonyl carbocations that\nare prepared via <b>CBZ6</b>-induced redox-neutral photocatalysis.\nIn this process, the photocatalytic oxidation of the β-fluoroalkyl\nα-carbonyl radical to the corresponding carbocation is the key\nstep. The β-fluoroalkyl α-carbonyl radical is generated\nin situ by the addition of a polyfluoroalkyl radical, which is generated\nby the photocatalytic fragmentation of polyfluoroalkyl sulfonyl chloride,\nto α,β-unsaturated carbonyls. The high <i>E</i><sub>00</sub> value of <b>CBZ6</b> (3.19 V vs the saturated\ncalomel electrode), which corresponds with the absorbed photoenergy,\ncontributes to the high catalytic reactivity.