Cp∗Rh/Ag catalyzed C–H activation/cyclization sequences of NH-sulfoximines to fused aza-polyheterocycles under gentle conditions
Jiapian Huang, Fei Liu, Feihua Du, Linghui Zeng, Zhiyuan Chen
Abstract
Disclosed herein is a novel Rh/Ag co-catalyzed SNH directed C–H activation and C–H/N–H bond functionalization protocol of free NH-sulfoximines with hypervalent iodonium ylides. With the aid of AgOTf, these C–H functionalization/cyclization sequences could be achieved at room temperature conditions. The reaction employed EtOH as a “green” solvent and low catalyst loading was required under an oxygen/water-insensitive condition. Under this mild protocol, a wide range of polyheterocyclic sulfoximines bearing fused saturated carbo(hetero)cycles are readily prepared, even toward a complex pharmaceutical Folliculin analog. An interesting Baeyer-Villiger oxidation reaction to access sulfoximine N-oxide with an expanded ester cycle was also achieved.