The Intriguing Reactivity of Functionalized β-Amino Alcohols with Glyoxal: Application to a New Expedient Enantioselective Synthesis of <i>trans</i>-6-Alkylpipecolic Acids
作者:Claude Agami、Sébastien Comesse、Catherine Kadouri-Puchot
DOI:10.1021/jo010780+
日期:2002.4.1
New beta-amino alcohols possessing a vinylsilane moiety were reacted with glyoxal to produce lactones that were transformed in three steps in enantiopure pipecolic acid derivatives. The key step was a totally diastereoselective ene-iminium cyclization, whose mechanism can be viewed as a direct cyclization of the vinylsilane moiety onto the iminium ion. The reactivity of two beta-amino alcohols having
使具有乙烯基硅烷部分的新的β-氨基醇与乙二醛反应生成内酯,将内酯分三步转化为对映体纯的胡椒酸衍生物。关键步骤是完全非对映选择性的烯-亚胺环化,其机理可以看作是乙烯基硅烷部分直接环化到亚胺离子上。还检查了具有烯丙基硅烷终止剂的两种β-氨基醇的反应性。它们对乙二醛的反应性差异可归因于碳正离子的干预,碳正离子的行为随三甲基甲硅烷基的位置而异。