Ionic diamine rhodium complex catalyzed reductive N-heterocyclization of N-(2-nitroarylidene)amines

Okuro, Kazumi; Gurnham, Joanna; Alper, Howard

doi:10.1016/j.tetlet.2011.11.101

Cited by 39 publications

(13 citation statements)

References 23 publications

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“…The same ionic rhodium system cited in the previous paragraph also succeeded in catalyzing the reductive cyclization of N‐ (2‐nitroarylidene)amines to 2 H‐ indazoles (Scheme ) …”

Section: Synthesis Of N‐heterocycles By Intra‐molecular Cyclization Rmentioning

confidence: 85%

“…The same ionic rhodium system cited in the previous paragraph also succeeded in catalyzing the reductive cyclization of N-(2-nitroarylidene)amines to 2H-indazoles (Scheme 27). [126] Both electronwithdrawing and electrondonating substituents on the aryl ring were well tolerated, but R 2 need to be an alkyl group for the reaction to proceed with good yields. If R 2 was phenyl or allyl, 25 % yield or trace amounts of the indazole were obtained.…”

Section: Synthesis Of Other 5-membered N-heterocyclesmentioning

confidence: 99%

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Transition Metal Catalyzed Reductive Cyclization Reactions of Nitroarenes and Nitroalkenes

2019

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Nitroarenes are the entry point for the production of most nitrogen‐containing aromatic compounds. Thus, any transformation that leads directly from them to the final product allows saving one or more synthetic steps. This review deals with homogeneously catalyzed reactions leading to the formation of N‐heterocyclic compounds from nitroarenes or nitroalkenes in one pot. Reactions that lead to the intermediate formation of amines are not considered. Carbon monoxide is the most often employed reductant because it allows selective reactions, is cheap, and only produces CO2 as stoichiometric byproduct. However, the difficulty in handling pressurized CO has stimulated in recent years the development of CO‐surrogates, that is molecules able to liberate CO during the reaction. The use of phosphines and diols has also been developed in conjunction with molybdenum catalysts. The review focusses in more detail on the literature in the period 2006–2018, but reference to earlier work is made when necessary to put recent results in a more general context.

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“…The same ionic rhodium system cited in the previous paragraph also succeeded in catalyzing the reductive cyclization of N‐ (2‐nitroarylidene)amines to 2 H‐ indazoles (Scheme ) …”

Section: Synthesis Of N‐heterocycles By Intra‐molecular Cyclization Rmentioning

confidence: 85%

Section: Synthesis Of Other 5-membered N-heterocyclesmentioning

confidence: 99%

Transition Metal Catalyzed Reductive Cyclization Reactions of Nitroarenes and Nitroalkenes

2019

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“…Therefore, much effort has been devoted to the development of methods for the synthesis of (2 H )‐indazoles . Typical approaches have involved (a) the reaction of 2‐chloromethylaryl zinc reagents and aryldiazonium salts, (b) Rh‐catalyzed reductive N ‐cyclization of 2‐nitroarylidines, and (c) Pd‐catalyzed domino reactions of 2‐halophenylacetylenes with hydrazines . Alternatively, Fe‐ or Cu‐catalyzed intramolecular N−N bond formations of 2‐azidoarylimines have been developed .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of (2H)‐Indazoles from Azobenzenes Using Paraformaldehyde as a One‐Carbon Synthon

et al. 2019

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Rhodium(III)-catalyzed hydroxymethylation followed by intramolecular annulation of azobenzenes using paraformaldehyde as a valuable C1-feedstock is described. The method is readily extended to the coupling reaction between azobenzenes and trifluoroacetaldehyde. This transformation efficiently produces a range of C3-unsubstituted and C3-trifluoromethylated (2H)-indazoles, which are important targets in the development of novel bioactive compounds. Excellent chemoselectivity and functional group tolerance were observed. The synthetic transformation of C3-unsubstituted (2H)-indazoles highlights the utility of the developed method.

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“…The method provides a simple phosphacatalytic approach to a valuable N – N bond forming mode that has previously been accomplished via (super)stoichiometric reagent chemistry, 13,28 transition metal catalysis, 29 or alternative high energy azide substrates. 30 Whereas previous studies involving P III /P V =O redox cycling have focused primarily on ring strain arguments underpinning catalytic turnover of phosphine oxides by silane reductants, the results above suggest a dominant electronic component to the overall biphilic function of the phosphetane catalyst.…”

mentioning

confidence: 99%

A Biphilic Phosphetane Catalyzes N–N Bond-Forming Cadogan Heterocyclization via P^III/P^V═O Redox Cycling

et al. 2017

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A small ring phosphacycle (1,2,2,3,4,4-hexamethylphosphetane) is found to catalyze deoxygenative N-N bond-forming Cadogan heterocyclization of o-nitrobenzaldimines, o-nitroazobenzenes and related substrates in the presence of hydrosilane terminal reductant. The reaction provides a chemoselective catalytic synthesis of 2H-indazoles, 2H-benzotriazoles, and related fused heterocyclic systems with good functional group compatibility. On the basis of both stoichiometric and catalytic mechanistic experiments, the reaction is proposed to proceed via catalytic PIII/PV=O cycling, where DFT modelling suggests a turnover limiting (3+1) cheletropic addition between the phosphetane catalyst and nitroarene substrate. Strain/distortion analysis of the (3+1) transition structure highlights the controlling role of frontier orbital effects underpinning the catalytic performance of the phosphetane.

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Ionic diamine rhodium complex catalyzed reductive N-heterocyclization of N-(2-nitroarylidene)amines

Cited by 39 publications

References 23 publications

Transition Metal Catalyzed Reductive Cyclization Reactions of Nitroarenes and Nitroalkenes

Transition Metal Catalyzed Reductive Cyclization Reactions of Nitroarenes and Nitroalkenes

Synthesis of (2H)‐Indazoles from Azobenzenes Using Paraformaldehyde as a One‐Carbon Synthon

A Biphilic Phosphetane Catalyzes N–N Bond-Forming Cadogan Heterocyclization via P^III/P^V═O Redox Cycling

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Ionic diamine rhodium complex catalyzed reductive N-heterocyclization of N-(2-nitroarylidene)amines

Cited by 39 publications

References 23 publications

Transition Metal Catalyzed Reductive Cyclization Reactions of Nitroarenes and Nitroalkenes

Transition Metal Catalyzed Reductive Cyclization Reactions of Nitroarenes and Nitroalkenes

Synthesis of (2H)‐Indazoles from Azobenzenes Using Paraformaldehyde as a One‐Carbon Synthon

A Biphilic Phosphetane Catalyzes N–N Bond-Forming Cadogan Heterocyclization via PIII/PV═O Redox Cycling

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A Biphilic Phosphetane Catalyzes N–N Bond-Forming Cadogan Heterocyclization via P^III/P^V═O Redox Cycling