| Hypervalent iodine reagents have attracted much attention as easily accessible,stable,efficient and environmentally benign oxidants,which are extensively used in organic synthetic chemistry.The functionalization of styrenes is very important in organic synthesis.The selective functionalization of the C(sp~2)–H bond of the styrenes with the retention of double bonds can provide many important functionalized styrenes products.In this paper,hypervalent iodine reagent-mediated double bond-retained amidation and sulfonylation of styrenes C(sp~2)–H bonds have been developed.1.A selective vinyl C–H amidation of 4-alkoxystyrenes with dibenzenesulfonimides has been developed for preparation of enamides.This method was mediated by a hypervalent iodine reagent through a radical dearomatization/aromatization process.It proceeded under metal-free conditions with high regioselectivity,providing the highly highly regioselective enamide products in 95%yields(Scheme 1).2.A hypervalent iodine reagent-mediated sulfonylation of styrenes with sulfonyl chlorides was developed for the synthesis of vinyl sulfones.The reaction proceeded under metal-free,mild and neutral conditions without extra oxidants or bases.It also exhibited functional groups compatibility,the substrates of both electron donor and electron withdraw groups have good reactivity,broad substrate scope and high chemo-selectivity,affording the vinyl sulfones in 90%yields(Scheme 2). |
