Fiaud’s Acid: A Brønsted Acid Catalyst for Enantioselective Friedel–Crafts Alkylation of Indoles with 2-Alkene-1,4-diones
作者:Sourav Chatterjee、Lukas Hintermann、Madhumita Mandal、Anushree Achari、Sreya Gupta、Parasuraman Jaisankar
DOI:10.1021/acs.orglett.7b01383
日期:2017.7.7
Fiaud’s acid (trans-1-hydroxy-2,5-diphenylphospholane 1-oxide), a phospholane-based phosphinic acid, is introduced as an efficient chiral Brønsted acid catalyst that mediates the asymmetric Friedel–Crafts alkylation of indoles with 2-butene-1,4-diones. With a catalyst loading of 10 mol %, the reaction proceeded smoothly to afford 2-(indol-3-yl)butane-1,4-diones in high yield (up to 82%) and high enantioselectivity
菲奥德酸(一种反式-1-羟基-2,5-二苯基膦环烷一氧化物)是一种基于膦酸酯的次膦酸,它是一种有效的手性布朗斯台德酸催化剂,可介导吲哚与2-丁烯-的不对称弗里德-克拉夫茨烷基化反应。 1,4-二酮。催化剂负载量为10 mol%时,反应平稳进行,以高收率(最高82%)和高对映选择性(最高ee 91%)提供了2-(吲哚-3-基)丁烷-1,4-二酮。一种这样的产物在重结晶后显示出提高的ee(98%)。反应条件足够温和,可以在室温下耐受敏感的功能,因此适合合成复杂的靶标。