Combining the catalytic enantioselective reaction of visible-light-generated radicals with a by-product utilization system. Issue 10 (1st September 2017) - Huang, Xiaoqiang
Abstract : We report an unusual reaction design in which a chiral bis-cyclometalated rhodium(iii ) complex enables the stereocontrolled chemistry of photo-generated carbon-centered radicals and at the same time catalyzes an enantioselective sulfonyl radical addition to an alkene. Abstract : We report an unusual reaction design in which a chiral bis-cyclometalated rhodium(iii ) complex enables the stereocontrolled chemistry of photo-generated carbon-centered radicals and at the same time catalyzes an enantioselective sulfonyl radical addition to an alkene. Specifically, employing inexpensive and readily available Hantzsch esters as the photoredox mediator, Rh-coordinated prochiral radicals generated by a selective photoinduced single electron reduction are trapped by allyl sulfones in a highly stereocontrolled fashion, providing radical allylation products with up to 97% ee. The hereby formed fragmented sulfonyl radicals are utilized via an enantioselective radical addition to form chiral sulfones, which minimizes waste generation.