Palladium-catalyzed alkenylation of quinoline-N-oxides via C-H activation under external-oxidant-free conditions.
The direct cross-coupling of quinoline-N-oxides with olefin derivatives has been realized using palladium acetate as the catalyst in the absence of external ligand and oxidant to give the corresponding 2-alkenylated quinolines and 1-alkenylated isoquinolines chemo- and regioselectively in 27-95% yield. The catalytic process is proposed to proceed via direct C-H bond activation of the quinoline-N-oxide with Pd(OAc)(2) followed by Heck coupling with the olefin. The resultant N-oxide of the alkenylated quinoline can oxidize the reduced Pd(0) to regenerate the Pd(II) active species and simultaneously release the 2-alkenylated quinoline without using any external oxidants and reductants.
Wu
Junliang
J
Henan Key Laboratory of Chemical Biology and Organic Chemistry, Department of Chemistry, Zhengzhou University, Zhengzhou 450052, PR China.
Cui
Xiuling
X
Chen
Lianmei
L
Jiang
Guojie
G
Wu
Yangjie
Y
D000179:Acrylates / Q000737:chemistry; D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D003497:Cyclic N-Oxides / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D011804:Quinolines / Q000737:chemistry*
D000179:Acrylates; D000475:Alkenes; D003497:Cyclic N-Oxides; D011804:Quinolines; D010165:Palladium; C040833:ethyl acrylate