摘要：SummaryPolarity-reversal catalysts enable otherwise sluggish or completely ineffective reactions which are characterized by unfavorable polar effects between radicals and substrates. We herein disclose that when irradiated by visible light, bromine can behave as a polarity-reversal catalyst. Hydroacylation of vinyl arenes, a three-component cascade transformation and deuteration of aldehydes were each achieved in a metal-free manner without initiators by using inexpensiveN-bromosuccinimide as the precatalyst. Light is essential to generate and maintain the active bromine radical during the reaction process. Another key to success is that HBr can behave as an effective hydrogen donor to turn over the catalytic cycles.Graphical abstractDisplay OmittedHighlights•Using bromine as a polarity-reversal catalyst to generate acyl radicals•Additive- and metal-free, atom- and step-economic, and operationally simple process•Using constant light-irradiation to induce and maintain bromine radicals•Access carbonyl compounds and deuterated aldehydes with wide substrate scopeChemistry; Organic chemistry; Green chemistry;
