Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas, USA.
Chirality. 2022 Oct;34(10):1338-1354. doi: 10.1002/chir.23492. Epub 2022 Jul 29.
Crystallization is one of the largest and most economical bulk purification techniques used in industry today. There has been an increase in demand for enantiomerically pure compound production for research, organic synthesis, pharmaceutical drug production, and other applications. Even after asymmetric synthesis, chiral purification will always be necessary. The focus of this review is on recent advances in chiral crystallization for the purification of enantiomers. A comprehensive discussion of three techniques and their mechanisms is provided, namely: attrition-enhanced deracemization, cocrystallization, and inorganic ionic cocrystallization. Several examples of attrition-enhanced deracemization are discussed. The key advantage of this technique is that it eliminates enantiomeric waste and can be used to produce enantiomeric excesses of greater than 99% from racemic mixtures. Chiral cocrystallization is examined, with over 60 cocrystallizing compounds, as an excellent means for enantiomeric enrichment. Selective chiral inclusion complexation was shown to be a novel approach for the formation of cocrystals. Chiral inorganic ionic cocrystallization is a new technique involving the formation of cocrystals between chiral ligands and certain metal salts in order to produce conglomerate crystal behavior in otherwise racemic compounds.
结晶是当今工业中最大和最经济的大规模纯化技术之一。人们对用于研究、有机合成、药物生产和其他应用的对映体纯化合物的需求不断增加。即使进行了不对称合成，手性纯化也始终是必要的。本综述的重点是手性结晶在对映体纯化方面的最新进展。全面讨论了三种技术及其机制，即：磨损增强外消旋化、共结晶和无机离子共结晶。讨论了几个磨损增强外消旋化的例子。该技术的主要优点是消除了对映体浪费，并且可以从外消旋混合物中生产出大于 99%的对映体过量。考察了手性共结晶，作为对映体富集的一种极好方法，涉及超过 60 种共结晶化合物。选择性手性包合络合被证明是形成共晶的一种新方法。手性无机离子共结晶是一种新技术，涉及手性配体与某些金属盐之间形成共晶，以便在原本外消旋的化合物中产生聚集体晶体行为。
