摘要
报道了一种经由二价铜催化饱和酮与肼或醛腙的串联反应合成1,3-二取代吡唑或1,3,4-三取代吡唑类化合物的简便和区域选择性新方法.从机理上看,1,3-二取代吡唑的生成经历了烯酮中间体的原位生成及其与肼的[3+2]环化反应,而1,3,4-三取代吡唑的生成则经历了烯酮中间体的原位生成及其与醛腙的[2+3]环化反应.与文献方法相比,该方法具有原料简单易得、底物适用范围广、区域选择性好、效率高、原子经济性优异等优势.
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.
作者
师晓楠
田苗苗
王慕华
张新迎
范学森
Shi Xiaonan;Tian Miaomiao;Wang Muhua;Zhang Xinying;Fan Xuesen(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)
出处
《有机化学》
SCIE
CAS
CSCD
北大核心
2019年第6期1630-1641,共12页
Chinese Journal of Organic Chemistry
基金
Project supported by the National Natural Science Foundation of China (No. 21572047)
the Plan for Scientific Innovation Talents of Henan Province (No. 184200510012)~~