A Cu-mediated preparation of 2-substitiuted pyrazolo[1,5-a]pyridines from N-benzoylpyridinium imides and terminal alkynes is described using stoichiometric Cu(OAc)2 as both the mediator and the oxidant. Extensive DFT calculations suggest a Cu(III) intermediate via disproportionation of Cu(II).
描述了使用化学计量的Cu(OAc)2作为介体和氧化剂,由N-苯甲酰基吡啶鎓酰亚胺和末端炔烃组成的Cu介导的2取代吡唑并[1,5- a ]吡啶的制备方法。广泛的DFT计算表明,通过Cu(II)歧化可以生成Cu(III)中间体。
[Cu( malo NHC)]-catalyzed synthesis of 2-aryl pyrazolo[5,1- a ]isoquinolines by annulation of N ′-(2-((trimethylsilyl)ethynyl)benzylidene)hydrazides with terminal aromatic alkynes
作者:Huixin Liu、Le Lu、Ruimao Hua
DOI:10.1016/j.tet.2017.09.037
日期:2017.11
A [Cu(maloNHC)]-catalyzed synthesis of 2-aryl pyrazolo[5,1-a]isoquinolines via annulation of N′-(2-((trimethylsilyl)ethynyl)benzylidene)hydrazides with terminal aromatic alkynes was developed.
A [的Cu(马洛NHC)] -催化的合成2-芳基吡唑并[5,1-一个]异喹啉通过的环ñ ' - (2 - ((三甲基甲硅烷基)乙炔基)亚苄基)酰肼与终端芳香炔被开发。
A cascade AgOTf-catalyzed chemoselective approach to 3,5/1,3-disubstitued pyrazoles from propargylic alcohols and para-tolylsulfonohydrazide has been developed. Good chemoselectivity is observed depending on the different substituents in the alkyne moiety of the propargylic alcohols, generating two different kinds of products through different aromatization mechanisms. The pyrazolo[5,1-a]isoquinoline skeleton can also be effectively constructed by this method through a cascade bicyclization process.