Department of Chemistry, Georgetown University, Washington, D.C. 20057, USA.
J Am Chem Soc. 2013 Aug 21;135(33):12200-3. doi: 10.1021/ja406259p. Epub 2013 Aug 6.
A stereodynamic chemosensor having a parallel arrangement of a substrate-binding salicylaldehyde unit and an adjacent pyridyl N-oxide fluorophore undergoes rapid condensation with chiral amino alcohols and subsequent asymmetric transformation of the first kind toward a single rotamer. Crystallographic analysis shows that the concomitant central-to-axial chirality imprinting is controlled by minimization of steric repulsion and by intramolecular hydrogen bonding between the bound amino alcohol and the proximate N-oxide group. The substrate binding event results in strong CD effects and characteristic fluorescence changes which can be used for instantaneous in situ determination of the absolute configuration, enantiomeric composition and total concentration of a variety of chiral amino alcohols. This chemosensing approach avoids time-consuming workup and purification steps, and it is applicable to minute sample amounts which reduces the use of solvents and limits waste production.
一种具有水杨醛单元和相邻吡啶 N-氧化物荧光团平行排列的立体动态化学传感器与手性氨基醇快速缩合，并随后向单一旋转体进行第一类不对称转化。晶体学分析表明，伴随的中心-轴向手性印迹由空间排斥的最小化和结合的氨基醇与邻近的 N-氧化物基团之间的分子内氢键控制。底物结合事件导致强烈的 CD 效应和特征荧光变化，可用于即时原位测定各种手性氨基醇的绝对构型、对映体组成和总浓度。这种化学传感方法避免了繁琐的后处理和纯化步骤，适用于微量样品，减少了溶剂的使用并限制了废物的产生。
