Semistabilized Diazatrienyl Anions from Pyridine Imines and Acetylenes: An Access to (Z)-Stilbene/Imidazopyridine Ensembles, Benzyl Imidazopyridines, and Beyond

Ivan A Bidusenko; Elena Yu Schmidt; Igor A Ushakov; Alexander V Vashchenko; Nadezhda I Protsuk; Vladimir B Orel; Nadezhda M Vitkovskaya; Boris A Trofimov

doi:10.1021/acs.joc.2c01372

Semistabilized Diazatrienyl Anions from Pyridine Imines and Acetylenes: An Access to (Z)-Stilbene/Imidazopyridine Ensembles, Benzyl Imidazopyridines, and Beyond

J Org Chem. 2022 Sep 16;87(18):12225-12239. doi: 10.1021/acs.joc.2c01372. Epub 2022 Aug 31.

Authors

Ivan A Bidusenko¹, Elena Yu Schmidt¹, Igor A Ushakov¹, Alexander V Vashchenko¹, Nadezhda I Protsuk¹, Vladimir B Orel^{1

2}, Nadezhda M Vitkovskaya², Boris A Trofimov¹

Affiliations

¹ E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 Favorsky Str., 664033 Irkutsk, Russia.
² Laboratory of Quantum-Chemical Modeling of Molecular Systems, Irkutsk State University, 1 K. Marx Street, 664003 Irkutsk, Russia.

PMID: 36044622
DOI: 10.1021/acs.joc.2c01372

Abstract

Semistabilized diazatrienyl anions are generated by the reaction of 2-pyridylarylimines with arylacetylenes in superbase systems MO^tBu (M = Li, Na, K)/DMSO at ambient temperature for 15 min. The initial intermediate N-centered propargyl-1,3-diaza-1,3,5-trienyl anions undergo intermolecular cyclization to benzyl imidazopyridine anions (formally [3 + 2] cycloaddition), further intercepting a second molecule of the starting pyridylimines or a proton of medium to afford (Z)-stilbene/imidazopyridine ensembles and benzyl imidazopyridines. The charge distribution in all intermediate anions and their synthetic evolution are consistent with quantum-chemical analysis (B2PLYPD/6-311+G**//B3LYP/6-31+G*).