Direct Functionalization of C(sp2)-H Bond in Nonaromatic Azaheterocycles: Palladium-Catalyzed Cross-Dehydrogenative Coupling (CDC) of 2 H-Imidazole 1-Oxides with Pyrroles and Thiophenes

Alexey A Akulov; Mikhail V Varaksin; Valery N Charushin; Oleg N Chupakhin

doi:10.1021/acsomega.8b02916

Direct Functionalization of C(sp²)-H Bond in Nonaromatic Azaheterocycles: Palladium-Catalyzed Cross-Dehydrogenative Coupling (CDC) of 2 H-Imidazole 1-Oxides with Pyrroles and Thiophenes

ACS Omega. 2019 Jan 10;4(1):825-834. doi: 10.1021/acsomega.8b02916. eCollection 2019 Jan 31.

Authors

Alexey A Akulov¹, Mikhail V Varaksin^{1

2}, Valery N Charushin^{1

2}, Oleg N Chupakhin^{1

2}

Affiliations

¹ Department of Organic & Biomolecular Chemistry, Ural Federal University, 19 Mira Street, 620002 Ekaterinburg, Russia.
² Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 22 S. Kovalevskaya Street, 620041 Ekaterinburg, Russia.

Abstract

The C(sp²)-H bond functionalization methodology was first applied to carry out the palladium-catalyzed oxidative C-H/C-H coupling reactions of 2H-imidazole 1-oxides with pyrroles and thiophenes. As a result, a number of novel 5-heteroarylated 2H-imidazole 1-oxides, which are of particular interest in the design of bioactive molecules and advanced materials, have been synthesized in yields up to 78%. The detailed H/D-exchange experiments have also been performed to elucidate some mechanistic features of this cross-dehydrogenative coupling process.