Organocatalytic Michael Addition of Indoles to α-Substituted Enals by Using a Diazepane Carboxylate Catalyst
作者:Florent Larnaud、Adamo Sulpizi、Nicklas O. Häggman、Jonathan M. E. Hughes、Damien F. Dewez、James L. Gleason
DOI:10.1002/ejoc.201700469
日期:2017.5.10
conjugate addition of indoles to α-substituted enals is achieved by using a diazepane carboxylate catalyst under mild conditions (20 mol-% catalyst, 20 mol-% TFA, acetonitrile, –20 °C). The low basicity and high nucleophilicity of this catalyst overcomes the limitations of allylic 1,3 strain in the intermediate iminium ions, which is normally observed with secondary-amine catalysts. Conjugate addition of
通过在温和的条件下(20摩尔%的催化剂,20摩尔%的TFA,乙腈,–20°C)使用二氮杂环庚烷羧酸盐催化剂,将吲哚共轭添加到α-取代的烯醛中。该催化剂的低碱性和高亲核性克服了中间体亚胺离子中烯丙基1,3应变的局限性,这在仲胺催化剂中通常会观察到。证明了一系列取代的吲哚以及富含电子的芳族化合物与各种α-取代的烯类的共轭添加。