The use of enaminones and enamines as effective synthons for MSA-catalyzed regioselective synthesis of 1,3,4-tri- and 1,3,4,5-tetrasubstituted pyrazoles
作者:Liancheng Duan、Hui Zhou、Yucheng Gu、Ping Gong、Mingze Qin
DOI:10.1039/c9nj03701b
日期:——
In the present work, an efficient regioselective synthesis of 1,3,4-tri- and 1,3,4,5-tetrasubstituted pyrazoles via a methanesulfonic acid (MSA)-catalyzed reaction of hydrazones with enaminones or enamines is reported. Mechanistically, the formation of the title compounds involves the [2+3] cycloaddition of hydrazones with enaminones or enamines followed by aromatization with acid and oxygen. This
在本工作中,已报道了通过甲磺酸(MSA)催化的azo与烯胺酮或烯胺的反应有效地区域选择性合成1,3,4-三-和1,3,4,5-四取代的吡唑。从机理上讲,标题化合物的形成涉及与烯胺酮或烯胺的[2 + 3]环加成,然后用酸和氧进行芳构化。在温和条件下使用各种,烯胺酮和烯胺进行这种方便的方法具有良好的耐受性,从而可以以良好或极好的收率提供产品。与文献方法相比,该策略具有诸如可经济获得的材料,无金属催化,优异的区域选择性和高效率等优点。