Rhodium(iii)-catalyzed [3 + 3] annulation reactions of N-nitrosoanilines and cyclopropenones: an approach to functionalized 4-quinolones

Abstract

We report Rh(iii)-catalyzed [3 + 3] annulation reactions for the preparation of functionalized 4-quinolones from available N-nitrosoanilines and cyclopropenones.

Rhodium(III)-Catalyzed Redox-Neutral [3+3] Annulation of N-nitrosoanilines with Cyclopropenones: A Traceless Approach to Quinolin-4(1H)-One Scaffolds

“…Therefore, in continuation of our recent efforts on transition-metal-catalyzed C-H annulations for the construction of heterocyclic scaffolds [31][32][33][34][35][36], we surprisingly found a new redox-neutral [3+3] annulation of N-nitrosoanilines with cyclopropenones [37][38][39] to generate a different substituted quinolin-4(1H)-one scaffold (Scheme 1c), which is a desirable privileged structure for further drug discovery. However, coincidentally, a similar work was reported by Cheng [40] after our work was finished and ready to submit. Compared with Cheng's strategy, this method without extra additives also enables the efficient preparation of quinolin-4(1H)-ones in a much shorter time (2 h vs. 12 h), and has a good substrate scope.…”

Recent Advances on Synthetic Methodology Merging C–H Functionalization and C–C Cleavage

“…The Chen group developed the Rh-catalyzed coupling of N -nitrosoanilines 98 and diphenylcyclopropenones 99 to get 4-quinolone scaffolds 100 ( Scheme 13 ) [ 62 ]. In this case, the N -nitroso moiety exerted the role of directing group for the ortho -C–H metalation of the substrates 98 .…”

N‐Nitroso As A Novel Directing Group in Transition‐Metal‐Catalyzed C(sp2)−H Bond Functionalizations of N‐Nitrosoanilines

“…The detailed investigation on the cycloaddition reaction established that N ‐nitrosoaniline could couple with cyclopropenone when exposed in a mixture of [Cp*RhCl 2 ] 2 (2 mol%), Ag 2 SO 4 (1.2 eq.) and NaF (50 mol%) in trifluoroethanol at 100 °C (Scheme 25, Condition A) [57] . 10% deuterium insertion at the ortho ‐position of N ‐nitrosoaniline concluded the reversibility of this reaction.…”