钌和铑催化的N-芳基吡唑苯环中邻位C-H键的直接羰基化反应。

Ruthenium- and rhodium-catalyzed direct carbonylation of the ortho C-H bond in the benzene ring of N-arylpyrazoles.

作者信息

Asaumi Taku, Matsuo Takuya, Fukuyama Takahide, Ie Yutaka, Kakiuchi Fumitoshi, Chatani Naoto

机构信息

Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.

出版信息

J Org Chem. 2004 Jun 25;69(13):4433-40. doi: 10.1021/jo049864j.

DOI:10.1021/jo049864j

PMID:15202898

Abstract

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 Ru(3)(CO)(12) or Rh(4)(CO)(12) resulted in the site-selective carbonylation of the ortho C-H bonds in the benzene ring to give the corresponding ethyl ketones. A variety of functional groups on the benzene ring can be tolerated. N-Phenylpyrazoles have higher reactivities than would be expected, based on the pK(a) values of the conjugate acid of pyrazole. The choice of solvent for this reaction is significant, and N, N-dimethylacetamide (DMA) gives the best result.

摘要

描述了通过钌或铑配合物催化N-苯基吡唑苯环中C-H键的直接羰基化反应。在Ru₃(CO)₁₂或Rh₄(CO)₁₂存在下，N-苯基吡唑与一氧化碳和乙烯反应，导致苯环中邻位C-H键发生位点选择性羰基化，生成相应的乙基酮。苯环上的各种官能团均可耐受。基于吡唑共轭酸的pKa值，N-苯基吡唑具有比预期更高的反应活性。该反应中溶剂的选择很重要，N, N-二甲基乙酰胺（DMA）效果最佳。