Dynamic Spin-Controlled Enantioselective Catalytic Chiral Reactions

Enantioselective catalytic chiral reactions are important to all aspects of life sciences. Here we present the first utilization of the chiral induced spin selectivity (CISS) effect to form, enantioselectively, sp³ chiral centers in catalytic reactions, starting from achiral reagents. The enantiomeric symmetry is broken by affecting spin-controlled different reaction dynamics toward each of the enantiomers, using magnetic substrates. Two catalytic reactions are used for this purpose: a sulfide to sulfoxide oxidation and a Diels-Alder cycloaddition reaction, both catalyzed by hematite (Fe₂O₃). The proof of concept was evaluated by circular dichroism measurements and by chiral high-performance liquid chromatography techniques. These results provide direct evidence that the directionality of the electron spin can break enantiomeric symmetry, enabling asymmetric catalysis without using chiral reagents, solvents, or catalysts.