Sulfoxonium Ylides as a Carbene Precursor in Rh(III)-Catalyzed C–H Acylmethylation of Arenes

Organic Letters, Journal Year: 2017, Volume and Issue: 19(19), P. 5256 - 5259

Published: Sept. 13, 2017

Sulfoxonium ylides act as an efficient carbene precursor in rhodium(III)-catalyzed C-H acylmethlyation of a variety arenes assisted by different chelating groups, and both aryl- alkyl-substituted β-carbonyl sulfoxonium are applicable. The system proceeded under redox-neutral conditions with broad scope, high efficiency, functional group tolerance.

Language: Английский

---

Selective Cyclization of Arylnitrones to Indolines under External Oxidant-Free Conditions: Dual Role of Rh(III) Catalyst in the C–H Activation and Oxygen Atom Transfer

Journal of the American Chemical Society, Journal Year: 2015, Volume and Issue: 137(15), P. 4908 - 4911

Published: April 7, 2015

The first example of Rh(III)-catalyzed cyclization arylnitrones to indolines under external oxidant-free conditions is presented. An intermolecular coupling with internal alkynes made possible by the dual role Cp*Rh(III) catalyst mediating both C-H bond activation and O-atom transfer. Synthetically important pharmacologically privileged indoline derivatives were obtained in good yields high diastereoselectivity.

Language: Английский

---

Enaminones as Synthons for a Directed C−H Functionalization: Rh^III‐Catalyzed Synthesis of Naphthalenes

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(32), P. 9384 - 9388

Published: June 15, 2016

The use of enaminones as effective synthons for a directed C-H functionalization is reported. Proof-of-concept protocols have been developed the Rh(III) -catalyzed synthesis naphthalenes, based on coupling with either alkynes or α-diazo-β-ketoesters. Two inherently reactive functionalities (hydroxy and aldehyde groups) are integrated into newly formed cyclic framework broad range substituents tolerated, rendering target products readily available further elaboration.

Language: Английский

---

Rhodium-catalyzed C–C coupling reactions via double C–H activation

Organic & Biomolecular Chemistry, Journal Year: 2016, Volume and Issue: 14(20), P. 4554 - 4570

Published: Jan. 1, 2016

Various rhodium-catalyzed double C–H activations are reviewed. These powerful strategies have been developed to construct C–C bonds, which might be widely embedded in complex aza-fused heterocycles, polycyclic skeletons and heterocyclic scaffolds. In particular, rhodium(III) catalysis shows good selectivity reactivity functionalize the bond, generating reactive organometallic intermediates most of coupling reactions. Generally, intermolecular, intramolecular multi-component reactions via with or without heteroatom-assisted chelation discussed this review.

Language: Английский

---

Structures of Reactive Donor/Acceptor and Donor/Donor Rhodium Carbenes in the Solid State and Their Implications for Catalysis

Journal of the American Chemical Society, Journal Year: 2016, Volume and Issue: 138(11), P. 3797 - 3805

Published: Feb. 24, 2016

Owing to its tremendous preparative importance, rhodium carbene chemistry has been studied extensively during past decades. The invoked intermediates have, however, so far proved too reactive for direct inspection, and reliable experimental information extremely limited. A series of X-ray structures pertinent this type, together with supporting spectroscopic data, now closes gap provides a detailed picture the constitution conformation such species. All complexes were prepared by decomposition diazoalkane precursor an appropriate source; they belong either dirhodium(II) tetracarboxylate that enjoys widespread use, or class mononuclear half-sandwich carbenes Rh(III), which show considerable potential. data correct refine previous computational studies but corroborate currently favored model prediction stereochemical course catalyzed cyclopropanations, is likely also applicable other reactions. Emphasis put on stereoelectronic rather than steric arguments, dipole acceptor substituent flanking center being major selectivity determining factor. Moreover, very subtle influence exerted anionic ligands Rh(III) chemical character resulting species documented homologous halide complexes. Finally, isolation N-bonded Rh(II) complex showcases hindrance represents inherent limitation chosen methodology.

Language: Английский

---

Enantiodivergent Desymmetrization in the Rhodium(III)‐Catalyzed Annulation of Sulfoximines with Diazo Compounds

Angewandte Chemie International Edition, Journal Year: 2018, Volume and Issue: 57(47), P. 15534 - 15538

Published: Oct. 11, 2018

RhIII - and IrIII -catalyzed asymmetric C-H functionalization reactions of arenes have relied on the employment chiral /IrIII cyclopentadienyl catalysts, introduction carboxylic acids to achiral Cp*RhX2 integration both strategies. Despite considerable progress, each reaction only provided a specific configuration enantioenriched product when using particular catalyst. Reported in this work is enantiodivergent coupling sulfoximines with various diazo compounds by desymmetrizing annulation. The enantiodivergence was enabled judicious choice acids, enantioselectivity correlates steric bias acid sulfoximine.

Language: Английский

---

From Indoles to Carbazoles: Tandem Cp*Rh(III)-Catalyzed C–H Activation/Brønsted Acid-Catalyzed Cyclization Reactions

ACS Catalysis, Journal Year: 2015, Volume and Issue: 5(11), P. 6453 - 6457

Published: Sept. 28, 2015

A tandem Cp*Rh(III)-catalyzed C–H activation/Brønsted acid-catalyzed intramolecular cyclization allows a facile synthesis of carbazoles from readily available indoles. The reaction proceeds under rather mild conditions with the generation water and N2 as only byproducts. Broad substrate scope, excellent functional group tolerance, high yields were observed. benzannulation pyroles for indoles is also feasible using same protocol.

Language: Английский

---

Thioamide‐Directed Cobalt(III)‐Catalyzed Selective Amidation of C(sp³)−H Bonds

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(52), P. 16550 - 16554

Published: Oct. 28, 2017

A mild, oxidant-free, and selective Cp*CoIII -catalyzed amidation of thioamides with robust dioxazolone amidating agents via C(sp3 )-H bond activation to generate the desired amidated products is reported. The method efficient allows for C-H a wide range functionalized aryl-, heteroaryl-, alkyl-substituted dioxazolones under conditions. observed regioselectivity towards primary supported by computational studies cyclometalation proposed proceed means an external carboxylate-assisted concerted metalation/deprotonation mechanism. reported rare example use directing group other than commonly used pyridine quinolone classes functionalization first exploit thioamides.

Language: Английский

---

Rhodium(III)-Catalyzed Synthesis of Naphthols via C–H Activation of Sulfoxonium Ylides

Organic Letters, Journal Year: 2017, Volume and Issue: 19(16), P. 4307 - 4310

Published: Aug. 7, 2017

Direct and efficient synthesis of 1-naphthols has been realized via Rh(III)-catalyzed C-H activation sulfoxonium ylides subsequent annulation with alkynes, where the ylide functioned as a new traceless bifunctional directing group. This reaction occurred under redox-neutral conditions broad substrate scope.

Language: Английский

---

C–F Bond Cleavage Enabled Redox-Neutral [4+1] Annulation via C–H Bond Activation

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 139(5), P. 1762 - 1765

Published: Jan. 18, 2017

Using α,α-difluoromethylene alkyne as a nontraditional one-carbon reaction partner, synthetically novel method for the construction of isoindolin-1-one derivatives via Rh(III)-catalyzed [4+1] annulation is reported. The 2-fold C-F bond cleavage not only enables generation desired product under an overall oxidant-free condition but also results in net migration carbon-carbon triple bond. In addition, present protocol exhibits tolerance wide spectrum functional groups due to mild conditions employed.

Language: Английский

---