Yan Yong, Shaikh Melad, Beard Matthew C, Gu Jing, Hendrix Isaac
Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182, USA.
National Renewable Energy Laboratory, Golden, CO 80401, USA.
Sci Adv. 2025 Jun 20;11(25):eadw5850. doi: 10.1126/sciadv.adw5850. Epub 2025 Jun 18.
We present a strategy to achieve absolute asymmetric catalysis that is effectively controlled by an external magnetic field via a spin-exchange reaction leveraging the chirality-induced spin selectivity effect. Using an external magnetic field to achieve asymmetric synthesis has long been desired. Here, we demonstrate 90% enantiomeric excess (ee) in [3 + 2] cycloadditions and 89% ee in aldol reactions, where the handedness of the product is determined by the ~±150 mT external magnetic polarization of a ferromagnet (FM). Our approach uses an enantioselective crystallization of racemic catalysts on a FM surface, using a small-scale crystallization vial connected to a bulk racemic solution. Racemic catalysts controllably crystallize into their respective enantiopure forms and are directly used in asymmetric reactions. Thus, we demonstrate that an external magnetic field can serve as a versatile symmetry-breaking tool to achieve highly enantioselective organic synthesis eliminating the need of any enantioenriched reagents.
我们提出了一种实现绝对不对称催化的策略，该策略通过利用手性诱导自旋选择性效应的自旋交换反应，由外部磁场有效控制。长期以来，人们一直希望利用外部磁场实现不对称合成。在此，我们展示了在[3 + 2]环加成反应中90%的对映体过量（ee）以及在醛醇缩合反应中89%的ee，其中产物的手性由铁磁体（FM）约±150 mT的外部磁极化决定。我们的方法是在FM表面使用连接到大量外消旋溶液的小规模结晶瓶，使外消旋催化剂进行对映选择性结晶。外消旋催化剂可控地结晶为各自的对映纯形式，并直接用于不对称反应。因此，我们证明了外部磁场可以作为一种通用的打破对称性的工具，以实现高度对映选择性的有机合成，而无需任何对映体富集试剂。
