Sequential Diastereoselective Addition of Allylic and Homoallylic Grignard Reagents to 2-Acyl-perhydro-1,3-benzoxazines and Ring-Closing Metathesis: an Asymmetric Route to Azepin-3-ol and Azocin-3-ol Derivatives
作者:Rafael Pedrosa、Celia Andrés、Agustín Gutiérrez-Loriente、Javier Nieto
DOI:10.1002/ejoc.200400836
日期:2005.6
Chiral 2-acyl-3-allyl-substituted perhydrobenzoxazines derived from (–)-8-aminomenthol react with allyl or homoallyl Grignard reagents to provide the corresponding tertiary alcohols in very good yields and with excellent diastereoselectivities. The 1,8- and 1,9-azadienes prepared in this way participate in RCM reactions to give good yields of seven- and eight-membered nitrogen heterocycles. The yields
衍生自 (-)-8-氨基薄荷醇的手性 2-酰基-3-烯丙基取代的全氢苯并恶嗪与烯丙基或高烯丙基格氏试剂反应,以非常好的收率和出色的非对映选择性提供相应的叔醇。以这种方式制备的 1,8- 和 1,9- 氮杂二烯参与 RCM 反应以产生良好的七元和八元氮杂环。当使用盐酸盐代替中性氮杂二烯时,RCM 反应的产率增加。手性佐剂的去除允许制备对映体纯的 azepin-3-ol 和 azocin-3-ol 衍生物。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)