Rhodium(II)‐Catalyzed C(sp³)−H Diamination of Arylcyclobutanes

Abstract

Activated by multiple consecutive oxidative radical‐polar crossover and desaturation processes, the selective diamination of arylcyclobutanes, which is difficult to perform by classical metallonitrene C−H insertion, was achieved in a short time by rhodium(II) catalysis using N‐fluorobenzenesulfonimide (NFSI) as the oxidant and nitrogen source.

Rhodium(II)-Catalyzed Desaturative [3+2] Tandem Cyclization of Arylcycloalkanes with β-Dicarbonyls

“…On the basis of the results presented above and previous research, , a palusible reaction mechanism has been proposed (Scheme d). The catalytic cycle starts with the NFSI-oxidized Rh­(II) catalysts, generating the Rh 2 (II,III)-ligated •NSI species [Rh 2 (II,III)-NSI], followed by the Rh 2 (II,III)-NSI species capturing the benzyl hydrogen in the cyclopentane substrate to form benzyl radical A .…”

“…Our group worked on studies of radical relay reactions and developed the single-electron oxidation reactions of the classical Rh­(II) catalyst previously used for nitrene transfer . Recently, the diamination reaction of arylcyclobutanes, which involves nine consecutive steps in a short period of time, has been successfully achieved using the rhodium­(II)/ N -fluorobenzenesulfonimide [Rh­(II)/NFSI] catalytic system (Scheme b) . During the study, we found that the Rh­(II)/NFSI catalytic system can efficiently achieve the desaturation activation of cycloalkanes in the presence of a base.…”

“…These results suggested that the reaction may involve a radical process. In previous work, we discovered that arylcyclobutane catalyzed by the Rh­(II)/NFSI system produces cyclobutene intermediates. To demonstrate that the cycloalkene intermediates were key intermediates in the developed reactions, pre-prepared arylcyclopentene 4 was introduced into this reaction mixture under standard conditions, and as expected, a 58% yield of target product 3al was obtained (Scheme c).…”

Dirhodium: carbene transformations and beyond

“…On the whole, the reaction mechanism includes three cycles, i.e., dehydration, 1 st amination and 2 nd amination. With this strategy, they also developed an efficient direct diamination protocol for arylcyclobutanes (Scheme 69) 117 and the desaturative [3 + 2] tandem cyclization of arylcycloalkanes with β-dicarbonyls (Scheme 70). 118 In the course of research, Wang and coworkers also found an interesting one-step route for allylic 1,3-diamination (Scheme 71).…”

Electrochemical dual α,β-C(sp3)–H functionalization of cyclic N-aryl amines

“…Hence, the development of simultaneous electrochemical methodologies for direct, efficient, and selective multiple C–H functionalization in a greener, more general, and economic way, facilitating potential practical applications, is still scarce and highly desirable yet challenging. 12 Notably, Lambert and co-workers reported an elegant electrophotocatalytic diamination of vicinal C(sp 3 )–H bonds by successive Ritter-type aminations, 13 using a combination of light and electrical energy, 14 and this strategy was also further successfully applied to the oxygenation of multiple adjacent C(sp 3 )–H bonds, 15 which are elegant examples of synthesizing multi-functionalized compounds by electrophotocatalysis with the potential for further applications.…”