描述了通过钌或铑络合物催化的N-苯基吡唑苯环中CH键的直接羰基化。在Ru 3(CO)12或Rh 4(CO)12存在下,N-苯基吡唑与一氧化碳和乙烯的反应导致苯环中邻位C-H键的位点选择性羰基化,得到相应的乙基酮。苯环上的各种官能团都是可以容忍的。基于p K a,N-苯基吡唑具有比预期更高的反应性吡唑共轭酸的分子量值。用于该反应的溶剂的选择是重要的,并且N,N-二甲基乙酰胺(DMA)给出了最好的结果。
Palladium nanoparticles supported on organofunctionalized kaolin as an efficient heterogeneous catalyst for directed C–H functionalization of arylpyrazoles
作者:Ping Yang、Yong-Sheng Bao
DOI:10.1039/c7ra11800g
日期:——
A heterogeneous catalyst system based on the immobilization of Pd0 nanoparticles onto organofunctionalized kaolin is reported with a view to introducing new synthetic routes of directed C–H functionalization of arylpyrazoles. Various characterization techniques revealed that the functional groups, 3-aminopropyltriethoxysilane (APTES) and phenyltrimethoxysilane, become strongly attached to the kaolin
A Rh(III)-catalyzed oxidative 1,3-aryl migration of α-arylallylic alcohols via Csp2–Csp3 σ bond activation has been developed. This method provides an efficient strategy to allow for allylic alcohol-based skeleton rearrangement, in which various secondary and tertiary α-arylallylic alcohols are rapidly converted to β-aryl-α, β-unsaturated ketones and aldehydes.
Ruthenium-Catalyzed C−H/CO/Olefin Coupling Reaction of <i>N</i>-Arylpyrazoles. Extraordinary Reactivity of <i>N</i>-Arylpyrazoles toward Carbonylation at C−H Bonds
The reaction of 1-arylpyrazoles with CO and ethylene in the presence of Ru-3(CO)(12) resulted in regioselective carbonylation at the ortho C-H bonds. While it is found that the pyrazole ring also functions as the directing group for C-H bond cleavage, the efficiency of the reaction depends on the position of the pyrazole ring.