A palladium-catalyzed Barluenga cross-coupling - Reductive cyclization sequence to substituted indoles

TETRAHEDRON

卷:94

Article

Rahman, S. M. Ashikur¹  Soderberg, Bjorn C. G.¹ 

[1] West Virginia Univ, C Eugene Bennett Dept Chem, Morgantown, WV 26506 USA

关键词: Palladium;    Catalysis;    Indole;    Barluenga-coupling;    Reductive-cyclization;   

DOI  :  10.1016/j.tet.2021.132331

来源: Elsevier

【 摘 要 】

A short and flexible synthesis of substituted indoles employing two palladium-catalyzed reactions, a Barluenga cross-coupling of p-tosylhydrazones with 2-nitroarylhalides followed by a palladium-catalyzed, carbon monoxide-mediated reductive cyclization has been developed. A one-pot, twostep methodology was further developed, eliminating isolation and purification of the cross-coupling product. This was accomplished by utilizing the initially added 0.025 equivalents of bis(triphenylphosphine)palladium dichloride, thus serving a dual role in the cross-coupling and the reductive cyclization. It was found that addition of 1,3-bis(diphenylphosphino)propane and carbon monoxide after completion of the Barluenga reaction afforded, in most cases, significantly better overall yields. (c) 2021 Elsevier Ltd. All rights reserved.

【 授权许可】

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