Synlett 2024; 35(16): 1844-1860
DOI: 10.1055/s-0042-1751540
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Adventures in CH-Arylation Chemistry

Peter Langer
a   Institut für Chemie, Universität Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany
b   Leibniz-Institut für Katalyse e. V. an der Universität Rostock, Albert-Einstein-Str. 29a, 18059 Rostock, Germany
› Author Affiliations


Abstract

The present article provides a personalized account on CH-arylation reactions employed for the synthesis of heterocycles. The presence of a nitro group allowed for direct and regioselective CH-arylations of pyrazoles, imidazoles, indoles and a variety of purine analogues. Direct CH-arylations without the presence of an activating nitro-group were employed for inter- and intramolecular reactions of purine derivatives, which allowed for the synthesis of a great variety of polycyclic systems. Domino C–N coupling / hydroamination / CH-activation reactions of diarylacetylenes with anilines allowed for the synthesis of polycondensated N-heterocycles. Products include indolo- and azaindolo[1,2-f]phenanthridines, quinolino[3′,4′:4,5]pyrrolo[1,2-f]phenanthridines, pyrimido[5′,4′:4,5]pyrrolo[1,2-f]phenanthridines, and benzothieno[2′,3′:4,5]pyrrolo[1,2-f]phenanthridines. The reaction of N-heterocycles, such as indoles, with 1,1-difluoroalkenes resulted in a twofold addition-elimination reaction to give 1,1-diaminoalkenes, which were transformed by CH-arylation into various polycondensated heterocycles, such as indoloisoquinolines, thienoindolizines, oxepines and helicenes. Pyridofluoranthenes, diindenopyrene and azadiindenopyrenes were prepared by a combination of Pd-catalyzed cross-coupling reactions with acid-mediated cycloisomerizations and Pd-catalyzed intramolecular CH-arylations. Bis(carbazoles), benzodithiazoles, benzodithiophenes and 2,5-diarylpyrroles were prepared by inter- and intramolecular CH-arylation reactions.



Publication History

Received: 24 October 2023

Accepted after revision: 13 November 2023

Article published online:
19 January 2024

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