Chin. J. Org. Chem. ›› 2019, Vol. 39 ›› Issue (6): 1630-1641.DOI: 10.6023/cjoc201903046 Previous Articles     Next Articles

Special Issue: 金属有机化学

Articles

由饱和酮与肼/醛腙的[3+2]/[2+3]环化反应区域选择性合成多取代吡唑

师晓楠, 田苗苗, 王慕华, 张新迎, 范学森   

  1. 河南师范大学化学化工学院 河南省有机功能分子与药物创新重点实验室 绿色化学介质与反应教育部重点实验室 新乡 453007
  • 收稿日期:2019-03-23 修回日期:2019-05-14 出版日期:2019-06-25 发布日期:2019-05-21
  • 通讯作者: 范学森 E-mail:xuesen.fan@htu.cn
  • 基金资助:

    国家自然科学基金(No.21572047)和河南省科技创新杰出人才(No.184200510012)资助项目.

Regioselective Synthesis of Substituted Pyrazoles via[3+2]/[2+3] Cyclization of Saturated Ketone with Hydrazine/Aldehyde Hydrazone

Shi Xiaonan, Tian Miaomiao, Wang Muhua, Zhang Xinying, Fan Xuesen   

  1. Henan Key Laboratory of Organic Functional Molecules and Drug Innovation, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007
  • Received:2019-03-23 Revised:2019-05-14 Online:2019-06-25 Published:2019-05-21
  • Contact: 10.6023/cjoc201903046 E-mail:xuesen.fan@htu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 21572047) and the Plan for Scientific Innovation Talents of Henan Province (No. 184200510012).

A highly convenient and regioselective synthesis of 1,3-disubstituted pyrazoles or 1,3,4-trisubstituted pyrazoles from Cu(Ⅱ)-catalyzed cascade reactions of saturated ketones with hydrazines or aldehyde hydrazones is presented. Mechanistically, the formation of 1,3-disubstituted pyrazoles involves the in situ generation of an enone intermediate followed by its[3+2] annulations with hydrazine. On the other hand, the formation of 1,3,4-trisubstituted pyrazoles is believed to go through a cascade process including enone formation and its subsequent[2+3] annulation with aldehyde hydrazone. Compared with literature methods, the notable features of the protocol include simple starting materials, general and broad substrate scope, high regioselectivity, good efficiency and excellent atom-economy.

Key words: pyrazole synthesis, Cu(Ⅱ) catalyzed reaction, C(sp3)-H functionalization, [3+2] annulation, [2+3] annulation