Chemoselective synthesis of substituted pyrazoles through AgOTf-catalyzed cascade propargylic substitution–cyclization–aromatization
作者:Su-Xia Xu、Lu Hao、Tao Wang、Zong-Cang Ding、Zhuang-Ping Zhan
DOI:10.1039/c2ob27016a
日期:——
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.
开发了一种瀑布式AgOTf催化的化学选择性方法,能够从丙炔醇和对甲苯磺酰肼得到3,5/1,3二取代的吡唑。根据丙炔醇中炔烃部分的不同取代基,观察到良好的化学选择性,通过不同的芳构化机制生成两种不同类型的产物。该方法还可以通过级联双环化过程有效构建吡唑[5,1-a]异喹啉骨架。