Cordonier Christopher E J, Satake Kyosuke, Atarashi Mikihiko, Kawamoto Yousuke, Okamoto Hideki, Kimura Masaru
Department of Chemistry, Faculty of Science, Okayama University, Tsushima-Naka 3-1-1, Okayama 700-8530, Japan.
J Org Chem. 2005 Apr 29;70(9):3425-36. doi: 10.1021/jo0500232.
[reaction: see text] The reaction of 2-methoxy-3H-azepines, in the presence or absence of a nucleophile, with N-bromosuccinimide (NBS) gave a regioselective 1,4-adduct from which the corresponding 2H-azepine derivatives were formed via base-promoted hydrogen bromide elimination, generally in moderate to quantitative yield. Competitive formation of 4-bromo-2-methoxy-3H-azepine by electrophilic substitutuion or 3H-azepin-2-yl 2H-azepin-2-yl ether by transetherification was minimized at lower reaction temperatures. Quantitative substitution of 2-(2',4',6'-trichlorophenoxy)-2H-azepine derivatives, formed in moderate yield from the respective 3H-azepine and NBS in the presence of 2,4,6-trichlorophenol (TCP), by various nucleophiles gave the corresponding 2-substituted 2H-azepine. Among these nucleophiles were alkanethiol and alkylamine that are not tolerated in the reaction of 3H-azepine and NBS.
[反应：见正文] 在有或没有亲核试剂存在的情况下，2-甲氧基-3H-氮杂䓬与N-溴代琥珀酰亚胺（NBS）反应生成区域选择性的1,4-加合物，通过碱促进的溴化氢消除反应从该加合物形成相应的2H-氮杂䓬衍生物，产率一般为中等至定量。在较低反应温度下，亲电取代生成4-溴-2-甲氧基-3H-氮杂䓬或通过转醚化生成3H-氮杂䓬-2-基 2H-氮杂䓬-2-基醚的竞争反应被最小化。在2,4,6-三氯苯酚（TCP）存在下，由相应的3H-氮杂䓬和NBS以中等产率形成的2-(2',4',6'-三氯苯氧基)-2H-氮杂䓬衍生物，被各种亲核试剂定量取代，得到相应的2-取代的2H-氮杂䓬。在这些亲核试剂中，有烷硫醇和烷基胺，它们在3H-氮杂䓬与NBS的反应中是不被耐受的。
