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Acyl-Directed ortho-Borylation of Anilines and C7 Borylation of Indoles using just BBr₃.

ABSTRACT: Indoles are privileged heterocycles found in many biologically active pharmaceuticals and natural products. However, the selective functionalization of the benzenoid moiety in indoles in preference to the more reactive pyrrolic unit is a significant challenge. Herein we report that N-acyl directing groups enable the C7-selective C-H borylation of indoles using just BBr₃ . This transformation shows some functional-group tolerance and notably proceeds with C6 substituted indoles. The directing group can be readily removed in situ and the products isolated as the pinacol boronate esters. Acyl-directed electrophilic borylation can be extended to carbazoles and anilines with excellent ortho selectivity. 4-amino-indoles are amenable to this process, with acyl group installation and directed electrophilic C-H borylation enabling selective formation of C5-BPin-indoles.

SUBMITTER: Iqbal SA

PROVIDER: S-EPMC6856876 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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Acyl-Directed ortho-Borylation of Anilines and C7 Borylation of Indoles using just BBr3.

Iqbal Saqib A SA Cid Jessica J Procter Richard J RJ Uzelac Marina M Yuan Kang K Ingleson Michael J MJ

Angewandte Chemie (International ed. in English) 20190912 43

Indoles are privileged heterocycles found in many biologically active pharmaceuticals and natural products. However, the selective functionalization of the benzenoid moiety in indoles in preference to the more reactive pyrrolic unit is a significant challenge. Herein we report that N-acyl directing groups enable the C7-selective C-H borylation of indoles using just BBr3 . This transformation shows some functional-group tolerance and notably proceeds with C6 substituted indoles. The di ...[more]

PMID: 31461213

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