Photoinduced Radical-Ionic Transfer of Various Chlorofluorocarbons to Alkenes from Oxime-Based Surrogates

Abstract

Functional-group-transfer strategies that avoid the use of unsustainable chemicals are attractive for the development of green methodologies. Chlorofluorocarbons (CFCs) not only contribute to the depletion of the stratospheric ozone layer, but their gaseous nature also poses a serious threat in scientific laboratories. Hence, the design of effective and sustainable alternatives to CFCs is highly desirable. Herein, a practical CFC transfer platform for the addition of both a fluoroalkyl group and a chlorine substituent across alkenes by a photomediated redox-neutral manifold using bench-stable and easy-to-handle oxime-based surrogates is reported. The distinct reactivity of these tunable reagents allows for their single-electron reduction to trigger fragmentation driven by benzonitrile formation and loss of carbon dioxide. The other fragments released in that step, namely an electrophilic fluoroalkyl radical and a nucleophilic chloride anion, are subsequently transferred onto alkenes by a radical-ionic mechanism to deliver the desired chlorofluorocarbon products.