The direct carbonylation of C−H bonds in the benzene ring of N-phenylpyrazoles via catalysis by ruthenium or rhodium complexes is described. The reaction of N-phenylpyrazoles with carbon monoxide and ethylene in the presence of Ru3(CO)12 or Rh4(CO)12 resulted in the site-selectivecarbonylation of the ortho C−H bonds in the benzene ring to give the corresponding ethyl ketones. A variety of functional
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。
<i>ortho</i>
‐Allylation of 1‐Arylpyrazoles with Allyl Phenyl Ether
<i>via</i>
Iron‐Catalyzed CH Bond Activation under Mild Conditions
An iron salt and a bipyridine‐type ligand catalyze the ortho‐allylation of 1‐arylpyrazoles and congeners with allyl phenyl ether under mild conditions (0 °C). The ligand, an organozinc base, and the nature of the allylating reagent are crucial for the success of this reaction. Under these conditions, a competitive phenylation reaction is largely retarded, and cross‐coupling of the organozinc with the