Diastereo- and Enantioselective Synthesis of Vicinal Amino Alcohols by Oxa Michael Addition ofN-Formylnorephedrine to Nitro Alkenes
作者:Dieter Enders、Andreas Haertwig、Gerhard Raabe、Jan Runsink
DOI:10.1002/(sici)1099-0690(199809)1998:9<1771::aid-ejoc1771>3.0.co;2-p
日期:1998.9
conjugate additions to aliphatic (E)-nitro alkenes 2a–j were carried out in good yields (35-87%) and excellent diastereomeric excesses (de = 94–≥98%). After reduction of the nitro group and protection of the amino function (11a–h, 73-87%, both steps), the cleavage of the auxiliary occurred without epimerisation (69-99%) using Na/NH3. The Boc-protected 2-amino alcohols 12a–h could be obtained in good overall
报告了第一个分子间不对称 oxa Michael 加成物,在氢氧化物源中具有可去除的手性信息。由于使用对映纯氧亲核试剂作为手性氢氧化物等价物 N-甲酰基去甲麻黄碱 (7) 并且以良好的产率 (35-87%) 和优异的非对映体过量 (de = 94–≥98%)。在还原硝基和保护氨基官能团(11a-h,73-87%,两个步骤)后,使用 Na/NH3 进行辅助裂解,没有差向异构化(69-99%)。Boc 保护的 2-氨基醇 12a-h 可以以良好的总产率(30-58%,四步)和优异的非对映体和对映体过量(de,ee = 94-≥98%)获得。