Synthesis of Pyrazolo[5,1-<i>a</i>]isoquinolines and 8-Methylenepyrazolo[5,1-<i>a</i>]isoindoles via Regioselective C–C Coupling and Alkyne Hydroamination
作者:Xuesen Fan、Meng Yan、Yuanyuan Wang、Xinying Zhang
DOI:10.1021/acs.joc.5b01620
日期:2015.11.6
An efficient and convenient synthesis of pyrazolo[5,1-a]isoquinolines has been achieved via palladium-catalyzed Sonogashira coupling of terminal alkynes with 5-(2-bromophenyl)-1H-pyrazoles, in situ formed from the condensation of 1-(2-bromophenyl)buta-2,3-dien-1-ones with hydrazine hydrate, followed by 6-endo intramolecular alkyne hydroamination. More interestingly, 8-methylenepyrazolo[5,1-a]isoindoles
通过端炔与5-(2-溴苯基)-1H-吡唑的钯催化Sonogashira偶联,可以实现吡唑并[5,1- a ]异喹啉的高效,便捷合成,所述1-炔烃是由1-的缩合反应原位形成的。 (2-溴苯基)buta-2,3-dien-1-ones与水合肼,然后进行6-内分子内炔烃加氢胺化。更有趣的是,8- methylenepyrazolo [5,1-一个]异吲哚,吡唑并区域异构体[5,1-一个]异喹啉类,也可以由相同的起始材料通过端炔与5-初始分子间加氢胺化有选择地合成( 2-溴苯基)-1 H-吡唑类化合物,然后是钯催化的5- exo 分子内Heck偶联反应。