Department of Chemistry , Scripps Research Institute , La Jolla , California 92037 , United States.
Department of Chemistry , University of California , Los Angeles , California 90095 , United States.
J Am Chem Soc. 2020 Feb 26;142(8):3873-3879. doi: 10.1021/jacs.9b11422. Epub 2020 Feb 17.
The evolution of homochirality via attrition-enhanced deracemization (AED) of enantiomorphic solids is carried out using molecules that differ only in the isotopic composition of a phenyl group positioned remote from the chiral center. Enantioenrichment consistently favors the enantiomorph containing a deuterated phenyl group over the protio or C version, and the protio version is consistently favored over the C version. While these isotopic compounds exhibit identical crystal structures and solubilities, the trend in deracemization correlates with melting points. Understanding the origin of this isotope bias provides fundamental clues about overcoming stochastic behavior to direct the stereochemical outcome in attrition-enhanced deracemization processes. The energy required for breaking symmetry with chiral bias is compared for this near-equilibrium AED process and the far-from-equilibrium Soai autocatalytic reaction. Implications for the origin of biological homochirality are discussed.
通过对具有手性中心的对映异构体固体的消旋增强外消旋化（AED）作用，实现了手性的进化。所使用的分子仅在手性中心以外的苯基的同位素组成上有所不同。对映体富集始终有利于含有氘代苯基的对映异构体，而不是原或 C 型，并且原型始终优先于 C 型。虽然这些同位素化合物具有相同的晶体结构和溶解度，但消旋化的趋势与熔点相关。了解这种同位素偏差的起源为克服随机行为提供了基本线索，以指导消旋增强外消旋化过程中的立体化学结果。比较了这种近平衡 AED 过程和远离平衡的 Soai 自催化反应中打破手性偏差对称性所需的能量。讨论了对生物手性起源的影响。
