Transition-Metal-Free Cross-Coupling of Aryl and N-Heteroaryl Cyanides with Benzylic Zinc Reagents

Functionalized 4-benzylated pyridines can be efficiently prepared by a transition-metal-free cross-coupling between various benzylic zinc chlorides and substituted 4-cyanopyridines in THF/DMPU under microwave irradiation (40 degrees C, 0.5-1.5 h). Selective benzylations on polycyano-aromatics have also been achieved under these mild conditions. We also report a novel oxidative nudeophilic substitution of a hydrogen on 1,3-dicyanobenzene using benzylic zinc reagents.