Meisenheimer-Wheland Complexes between 1,3,5-Tris(N,N-dialkylamino)benzenes and 4,6-Dinitrotetrazolo[1,5-a]pyridine. Evidence of Reversible C-C Coupling in the SEAr/SNAr Reaction

Reactions between a superelectrophilic carbon reagent, 4,6-dinitrotetrazolopyridine, and 1,3,5-tris(N,N-dialkylamino)benzenes, a supernucleophilic carbon reagent series, afford C-C coupling products which are double sigma-complexes (W-M), Wheland-like on the 1,3,5-tris(N,N-dialkylamino)benzene moiety and Meisenheimer-like on the 4,6-dinitrotetrazolopyridine moiety. These complexes were moderately stable at low temperature, and they were characterized by NMR spectroscopy methods. H-1 NMR experiments at variable temperature strongly indicate that the formation of these complexes by a nucleophile/electrophile attack is a reversible process.