1996-38-9Relevant articles and documents
Cp?Ir(III)-Catalyzed Mild and Broad C-H Arylation of Arenes and Alkenes with Aryldiazonium Salts Leading to the External Oxidant-Free Approach
Shin, Kwangmin,Park, Sung-Woo,Chang, Sukbok
, p. 8584 - 8592 (2015)
Reported herein is the development of Cp?Ir(III)-catalyzed direct C-H arylation of arenes and alkenes using aryldiazonium tetrafluoroborates, the use of which as an aryl precursor and also as an oxidant via C-N2 bond cleavage was a key to success in achieving a mild and external oxidant-free procedure. Mechanistic experiments and DFT calculations revealed the turnover-limiting step to be closely related to the formation of an Ir(V)-aryl intermediate rather than the presupposed C-H cleavage. Under the developed mild arylation conditions, a wide range of benzamides were smoothly arylated. In addition, synthetic utility of the current C-H arylation procedure was also demonstrated successfully for the (Z)-selective arylation of enamides and C8-selective reaction of quinoline N-oxides.
Transition-Metal- A nd Light-Free Directed Amination of Remote Unactivated C(sp3)-H Bonds of Alcohols
Kurandina, Daria,Yadagiri, Dongari,Rivas, Monica,Kavun, Aleksei,Chuentragool, Padon,Hayama, Keiichi,Gevorgyan, Vladimir
supporting information, p. 8104 - 8109 (2019/06/13)
Due to the great value of amino alcohols, new methods for their synthesis are in high demand. Abundant aliphatic alcohols represent the ideal feedstock for the method development toward this important motif. To date, transition-metal-catalyzed approaches for the directed remote amination of alcohols have been well established. Yet, they have certain disadvantages such as the use of expensive catalysts and limited scope. Very recently, transition-metal-free visible-light-induced radical approaches have emerged as new powerful tools for directed remote amination of alcohols. Relying on 1,5-HAT reactivity, these methods are limited to β-or δ- A mination only. Herein, we report a novel transitionmetal- A nd visible-light-free room-temperature radical approach for remote β-, γ-, and δ-C(sp3)-N bond formation in aliphatic alcohols using mild basic conditions and readily available diazonium salt reagents.
Modular and Selective Arylation of Aryl Germanes (C?GeEt3) over C?Bpin, C?SiR3 and Halogens Enabled by Light-Activated Gold Catalysis
Dahiya, Amit,Fricke, Christoph,Funes-Ardoiz, Ignacio,Gevondian, Avetik G.,Schoenebeck, Franziska,Sherborne, Grant J.
supporting information, p. 15543 - 15548 (2020/06/22)
Selective C (Formula presented.) –C (Formula presented.) couplings are powerful strategies for the rapid and programmable construction of bi- or multiaryls. To this end, the next frontier of synthetic modularity will likely arise from harnessing the coupling space that is orthogonal to the powerful Pd-catalyzed coupling regime. This report details the realization of this concept and presents the fully selective arylation of aryl germanes (which are inert under Pd0/PdII catalysis) in the presence of the valuable functionalities C?BPin, C?SiMe3, C?I, C?Br, C?Cl, which in turn offer versatile opportunities for diversification. The protocol makes use of visible light activation combined with gold catalysis, which facilitates the selective coupling of C?Ge with aryl diazonium salts. Contrary to previous light-/gold-catalyzed couplings of Ar–N2+, which were specialized in Ar–N2+ scope, we present conditions to efficiently couple electron-rich, electron-poor, heterocyclic and sterically hindered aryl diazonium salts. Our computational data suggest that while electron-poor Ar–N2+ salts are readily activated by gold under blue-light irradiation, there is a competing dissociative deactivation pathway for excited electron-rich Ar–N2+, which requires an alternative photo-redox approach to enable productive couplings.
