MILD AND EFFICIENT ADDITION OF CARBON NUCLEOPHILES TO CONDENSED PYRIDINES: INFLUENCE OF STRUCTURE AND LIMITS OF APPLICABILITY
A number of azolo- and azinopyridines with varying substituents and annulated heterocycles were synthesized and examined in dearomatization reactions with carbon nucleophiles. Depending on the structure, the resulting covalent σ-adducts were formed either under basefree conditions or in Et3N-promoted process to give functionalized condensed dihydropyridines. Quantum-chemical calculations of the global electrophilicity index derived from FMO energies of azolopyridine series were performed to explain reactivity toward neutral and anionic C-nucleophiles. These values may be useful for qualitative prediction of particular reactivity pattern.