First selective direct mono-arylation of piperidines using ruthenium-catalyzed C-H activation

A Ru-catalyzed mono-arylation in alpha-position of saturated cyclic amines is reported employing a C-H activation protocol. Substitution of the pyridine directing group with a bulky group, e.g., trifluoromethyl in the 3-position, proved to be crucial to avoid bis-arylation. This highly selective transformation can be performed with different amines and arylboronate esters. Additionally, the directing group can be cleaved, taking advantage of an unprecedented detrifluoromethylation reaction.