Cobalt-Catalyzed Selective Synthesis of Isoquinolines Using Picolinamide as a Traceless Directing Group

Picolinamide
has first been employed as a traceless directing group
for the cobalt-catalyzed oxidative annulation of benzylamides with
alkynes to synthesize isoquinolines through C–H/N–H
bonds activation. Oxygen is
used as a terminal oxidant. This protocol exhibits good functional
group tolerance and excellent regioselectivity. Both terminal and
internal alkynes can be efficiently applied to this catalytic system
as substrates.