Spiroborate Ester-Mediated Asymmetric Synthesis of β-Hydroxy Ethers and Its Conversion to Highly Enantiopure β-Amino Ethers
作者:Kun Huang、Margarita Ortiz-Marciales、Wildeliz Correa、Edgardo Pomales、Xaira Y. López
DOI:10.1021/jo900666r
日期:2009.6.5
Borane-mediated reduction of aryl and alkyl ketones with α-aryl- and α-pyridyloxy groups affords β-hydroxy ethers in high enantiomeric purity (up to 99% ee) and in good yield, using as catalyst 10 mol % of spiroborate ester 1 derived from (S)-diphenylprolinol. Representative β-hydroxy ethers are successfully converted to β-amino ethers, with minor epimerization, by phthalimide substitution under Mitsunobu’s
使用 10 mol % 的螺硼酸酯1作为催化剂,通过硼烷介导的 α-芳基-和 α-吡啶氧基还原芳基和烷基酮,得到高对映体纯度(高达 99% ee)且产率良好的 β-羟基醚衍生自( S )-二苯基脯氨醇。通过在 Mitsunobu 条件下进行邻苯二甲酰亚胺取代,然后肼解以获得伯氨基醚,或者通过用硼烷进行酰亚胺还原,得到 β-2,3-二氢-1 H,代表性的 β-羟基醚可成功转化为 β-氨基醚,并伴有少量差向异构化-异吲哚醚。通过关键 β-羟基吡啶醚的甲磺化并用五元、六元和七元环杂环胺取代,还可以以优异的产率合成具有潜在生物活性的非外消旋 Mexiletine 和 nAChR 类似物。