Palladium-catalyzed C-H functionalization of pyridine N-oxides: highly selective alkenylation and direct arylation with unactivated arenes.
Two catalytic protocols of the oxidative C-C bond formation have been developed on the basis of the C-H bond activation of pyridine N-oxides. Pd-catalyzed alkenylation of the N-oxides proceeds with excellent regio-, stereo-, and chemoselectivity, and the corresponding ortho-alkenylated N-oxide derivatives are obtained in good to excellent yields. Direct cross-coupling reaction of pyridine N-oxides with unactivated arene was also developed in the presence of Pd catalyst and Ag oxidant, which affords ortho-arylated pyridine N-oxide products with high site-selectivity.
Cho
Seung Hwan
SH
Department of Chemistry and School of Molecular Science (BK21), Korea Advanced Institute of Science and Technology, Daejon 305-701, Republic of Korea.
Hwang
Seung Jun
SJ
Chang
Sukbok
S