Sodium dithionite as a bifunctional reagent for the cyanoalkylsulfonylation of Morita–Baylis–Hillman acetates with cycloketone oxime esters

For the first time, an inexpensive and readily available inorganic salt, sodium dithionite (Na₂S₂O₄), has been demonstrated for the single electron reduction of cycloketone oxime esters. The resultant cyanoalkyl radicals are efficiently transformed into cyanoalkyl sulfinates and subsequently intercepted by Morita-Baylis-Hillman (MBH) acetates. This novel methodology provides access to a wide variety of allylic cyanoalkylsulfones in a chemo-, regio- and stereo-selective manner. Importantly, this approach is transition-metal-, light-irradiation-free, offering a complementary pathway to existing cyanoalkylsulfonylation routes.