Triphenylphosphine/1,2-Diiodoethane-Promoted Formylation of Indoles with N,N-Dimethylformamide

Yu-Rong Zhu, Jin-Hong Lin*, Ji-Chang Xiao*

*SIOC, University of Chinese Academy of Sciences, Chinese Academy of Sciences (CAS), 345 Lingling Road, Shanghai, 200032, P. R. of China, Email: jchxiaosioc.ac.cn, jlinsioc.ac.cn

Y.-R. Zhu, J.-H. Lin, J.-C. Xiao, Synlett, 2022, 33, 259-263.

DOI: 10.1055/a-1675-1043

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Abstract

In a Ph₃P/ICH₂CH₂I-mediated formylation of indoles with DMF under mild conditions, a Vilsmeier-type intermediate is readily formed from DMF promoted by the Ph₃P/ICH₂CH₂I system. A one-step formylation process can be applied to various electron-rich indoles, but a hydrolysis needs to be carried out as a second step in the case of electron-deficient indoles.

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proposed mechanism

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Key Words

formylation, indoles, aldehydes, Vilsmeier-type intermediate, dimethylformamide

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ID: J72-Y2022