Lewis acid activation of pyridines for nucleophilic aromatic substitution and conjugate addition

A clean, mild and sustainable method for the functionalization of pyridines and their analogues is reported. A zinc-based Lewis acid is used to activate pyridine and its analogues towards nucleophilic aromatic substitution, conjugate addition, and cyclization reactions by binding to the nitrogen on the pyridine ring and activating the pyridine ring core towards further functionalization. Pyridine gets active: For the first time, the catalytic activation of the pyridine ring towards nucleophilic aromatic substitution, conjugate addition, and Diels-Alder reactions is reported. The method utilizes a cheap, non-toxic zinc-based Lewis acid, which binds to the nitrogen of the pyridine ring and activates it towards nucleophilic aromatic substitution. The reaction tolerates a variety of incoming groups and proceeds cleanly and under mild reaction conditions.