Improved preparation of alkyl 2-(3-indolyl)-3-nitroalkanoates under fully heterogeneous conditions: stereoselective synthesis of alkyl (E)-2-(3-indolyl)-2-alkenoates
作者:Roberto Ballini、Serena Gabrielli、Alessandro Palmieri、Marino Petrini
DOI:10.1016/j.tet.2008.04.014
日期:2008.6
the presence of basic alumina affords ethyl 2-(3-indolyl)-3-nitroalkanoates that are central intermediates for the preparation of tryptamines and carboline alkaloids. A base promoted elimination of nitrous acid from these nitroindolyl derivatives readily produces ethyl 2-(3-indolyl)-2-alkenoates with high E stereoselectivity. The latter compounds can be used as Michael acceptors in intra- and intermolecular
3-硝基-2-链烯酸乙酯可以由硝基烷和2-氧代乙酸乙酯在不均匀的条件下生成,这样可以最大程度地减少后处理程序,避免任何纯化步骤和直接操作硝基链烯系统。在碱性氧化铝的存在下,由其乙酰氧基前体原位形成的3-硝基-2-链烯酸乙酯与吲哚反应,得到2-(3-吲哚基)-3-硝基链烷酸乙酯,它们是制备色胺的主要中间体。咔啉生物碱。从这些硝基吲哚基衍生物中碱促进的亚硝酸消除容易产生具有高E立体选择性的2-(3-吲哚基)-2-链烯酸乙酯。后者化合物可以在与亲核试剂的分子内和分子间反应中用作迈克尔受体。