通过手性腈的无氰化物合成和醛肟脱水酶催化的坎普消除反应的结合,我们在此报道醛肟脱水酶在5-sub-4,5-二氢异恶唑的不对称开环中合成手性β的新应用-羟基腈,具有广泛的底物范围,出色的对映选择性(高达99%ee)和良好的周转率(高达11 s -1)。简单分离并用碱性试剂处理后,剩余的手性5-sub-4,5-二氢异恶唑可轻松转化为它们相应的β-羟基腈。使用定点诱变,证实了含亚铁血红素的活性位点,并提出了两种可能的去质子化途径。据我们所知,这是第一个用于从一个简单的烯烃一步一步构建手性羟基和腈基的酶促反应,这为合成β-羟基互补对映异构体提供了一种新颖而有用的策略腈。
Thiacrown Ether Technology in Lipase-Catalyzed Reaction: Scope and Limitation for Preparing Optically Active 3-Hydroxyalkanenitriles and Application to Insect Pheromone Synthesis
Both reaction rate and enantioselectivity in Pseudomonas cepacia lipase (PCL)-catalyzed hydrolysis of 3-hydroxyalkanenitrile acetates were significantly changed by the addition of catalytic amounts of thiacrown ether (1,4,8,11-tetrathiacyclotetradecane). Although the-reaction rate of various nitriles was accelerated, the enantioselectivity greatly depended on the nature of the substrate. Among 10 substrates tested, thiacrown ether offered highest enantioselectivity in PCL-catalyzed hydrolysis of 1-(cyanomethyl)propyl acetate. Forty or more times this crown ether, molarity based on the enzyme, was required to attain an acceptably high reaction rate and enantioselectivity. Applying this technology, we succeeded in synthesizing the optically pure attractant pheromone of ant Myrmica scabrinodis (A), (R)-3-octanol and its antipode of (S)-isomer in good overall yields.