Journal of the American Chemical Society, Vol.130, No.8, 2448-2449, 2008
A strategy for C-H activation of pyridines: Direct C-2 selective alkenylation of pyridines by Nickel/Lewis acid catalysis
The C-2 selective alkenylation of pyridine derivatives is achieved with a catalyst consisting of nickel and Lewis acid. Use of diorganozinc compounds as the Lewis acid catalyst gives C-2 monoalkenylation products, whereas AIMe(3) changes the reaction course to afford C-2 dienylated products, which are derived from double insertion of alkynes into the C(2)-H bond. The reaction demonstrates a broad substrate scope and proceeds with high chemo-, regio-, and stereoselectivities under mild conditions compared with previous examples of direct GM functionalization of pyridines.