Rhodium-Catalyzed NH-Indole-Directed C–H Carbonylation with Carbon Monoxide: Synthesis of 6H-Isoindolo[2,1-a]indol-6-ones

Abstract

An efficient synthesis of 6H-isoindolo[2,1-a]indol-6-ones through rhodium-catalyzed NH-indole-directed C-H carbonylation of 2-arylindoles with carbon monoxide has been developed. Preliminary mechanistic studies revealed that this reaction proceeds via N-H bond cleavage and subsequent C-H bond cleavage. Reaction monitoring via ESI-MS was used to support the formation of five-membered rhodacycle species in the catalytic cycle.

Rhodium‐Catalyzed Regioselective Ortho C−H Olefination of 2‐Arylindoles via NH‐Indole‐Directed C−H Bond Cleavage

“…On the basis of above experimental results and previous studies,,, a plausible catalytic cycle for the ortho ‐di‐olefination is proposed in Scheme . First, the coordination of 2‐phenyl‐1 H ‐indole to a Cp*Rh(III) center followed by N−H bond cleavage and subsequent ortho ‐C−H bond cleavage gives a five‐membered rhodacycle B, which could be detected by ESI‐MS analysis .…”

“…On the basis of above experimental results and previous studies,,, a plausible catalytic cycle for the ortho ‐di‐olefination is proposed in Scheme . First, the coordination of 2‐phenyl‐1 H ‐indole to a Cp*Rh(III) center followed by N−H bond cleavage and subsequent ortho ‐C−H bond cleavage gives a five‐membered rhodacycle B, which could be detected by ESI‐MS analysis . Thereafter, insertion of ethyl acrylate to the rohodim‐carbon bond of B generated the seven‐membered rhodacycle C. β‐Hydride elimination and subsequent reductive elimination of the intermediate C provided the mono‐olefinated product 3 a′ with Rh(I)Cp* which could be oxidized by Cu(II) to continue the second ortho ‐C−H olefination to release target product 3 a .…”

“…[17,18] Lan and You described palladium‐catalyzed N−H/C−H arylation of 2‐arylindoles with 1,2‐dihaloarenes . In a previous study, we described a rhodium‐catalyzed ortho ‐C−H carbonylation of 2‐arylindoles with carbon monoxide for the synthesis of 6 H ‐isoindolo[2,1‐α]indol‐6‐ones . Our ongoing interest in the catalytic C−H bond functionalization prompted us to explore transition‐metal‐catalyzed oxidative olefination of ortho ‐C−H bonds of 2‐arylindoles.…”

Isoindolinone Synthesis via One‐Pot Type Transition Metal Catalyzed C−C Bond Forming Reactions

“…Q. Huang et al [169] presented ar hodium-catalyzed synthesis of 6H-isoindolo[2,1-a]indol-6-one derivatives via oxidative NÀ H/CÀHc arbonylation of 2-arylindoles under atmosphericC Opressure (Scheme 85). The optimized conditions were applied to ab road substrates cope generating the titlec ompounds in moderate to very high yields.…”

Synthesis and theoretical activity of three steroid-derivatives on both aromatase and 17β-hydroxysteroid dehydrogenase Type 1 enzymes

“…In this study, three steroid derivatives were prepared using some chemical strategies: First stage. This step involved the preparation of an indol-steroid derivative (compound 2); it is noteworthy that several indol analogs have been synthesized using some reagents such as Nchlorosuccinimide [28], gold [29], rhodium [30], CuBr [31] and others. In this study, the compound 2 was prepared from formestane and diphenylhydrazine ( Figure 1).…”