Rh(iii)-catalyzed C–H activation/annulation of N-carbamoylindoles with CF₃-imidoyl sulfoxonium ylides for the divergent synthesis of trifluoromethyl-substituted (dihydro)pyrimidoindolones

Abstract

An efficient and straightforward strategy for the divergent synthesis of trifluoromethyl-substituted (dihydro)pyrimidoindolones via Rh(III)-catalyzed C-H activation/annulation of N-carbamoylindoles with CF3-imidoyl sulfoxonium ylides has been achieved. The cascade reaction might proceed...

Formal (4+2) cycloaddition of azoalkenes with trifluoromethylimidoyl sulfoxonium ylides: synthesis of trifluoromethyl pyridazine derivatives

“…6 Transition-metal-catalyzed cascade C–H activation/annulation reactions involving TFISYs have emerged as straightforward approach for building heterocycles that include benzopyrans, 7 naphthyridines, 8 isoquinolones, 9 and pyrimidoindolones. 10 Moreover, metal-free cycloaddition reactions involving TFISYs have attracted great interest in recent years because they are operationally simple, highly efficient, and scalable, which enables the construction of diverse heterocyclic skeletons. Cheng 11 and Wu 12 independently reported (3+3) annulation reaction of TFISYs with cyclopropenones or hydrazonoyl chlorides, which produced CF 3 -containing pyridones or triazines, respectively (Scheme 1a).…”

“…Guided by previous literature reports, 6–14 Scheme 5 presents a tentative reaction mechanism for the chemistry developed in this study. The anionic carbon in the imidoyl sulfoxonium ylide 1a (as exemplified by resonance structure I ) initially nucleophilically attacks the CC bond of α,β-unsaturated hydrazone 2a to generate zwitterionic intermediate II .…”