Synthesis 2022; 54(16): 3568-3587
DOI: 10.1055/a-1786-6578
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On the Copper-Promoted Backbone Arylation of Histidine-Containing Peptides Using Triarylbismuthines

Hwai-Chien Chan
,
Alexandre Gagnon
This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Centre in Green Chemistry and Catalysis (CGCC), and Boehringer Ingelheim Pharmaceuticals Inc. through a Scientific Advancement Grant.


This paper is dedicated to the memory Dr. Michael Bös for his remarkable contribution to the pharmaceutical industry in the Montreal area and his friendship.

Abstract

We report herein our detailed investigation on the histidine-directed backbone arylation of histidine-containing peptides using triarylbismuth reagents. The reaction proceeds on the backbone NH of the amino acid that precedes the histidine, the so-called n–1 position. The protocol is applicable to dipeptides where the histidine is located at the C-terminus and to tripeptides where the histidine occupies the central position. The transformation is promoted by copper(II) acetate in the presence of phenanthroline (Phen) and diisopropylethylamine in dichloromethane at 50 °C under oxygen. An excellent scope was observed for the triarylbismuthines. In all cases, the imidazole ring of the histidine is protected with a trityl group to prevent the arylation of the side chain. An ATCUN-like model is proposed to explain the observed results.

Supporting Information



Publication History

Received: 10 February 2022

Accepted after revision: 02 March 2022

Accepted Manuscript online:
02 March 2022

Article published online:
10 May 2022

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