This research pioneers a novel class of visible-light-driven chiral phosphine catalysts for highly enantioselective [2+2] cycloaddition reactions. We designed a series of bifunctional organocatalysts by covalently integrating a light-harvesting chromophore (phenothiazine or thioxanthone) with a privileged chiral phosphine framework (e.g., Binap). Under blue LED irradiation, these catalysts function synergistically: the photoexcited chromophore engages in triplet energy transfer to activate an electron-rich olefin (e.g., vinyl sulfone), while the phosphine moiety acts as a Lewis base to activate and organize an electron-deficient partner (e.g., maleimide) within a well-defined chiral environment. This dual activation mechanism facilitates stereocontrolled cross-coupling under mild conditions. The optimized catalyst achieved the model cycloaddition in 92% yield and 94% enantiomeric excess (ee). The reaction exhibits broad substrate scope, tolerating various styrenes, sulfones, and maleimide derivatives to afford densely functionalized cyclobutanes with high enantioselectivity (85-96% ee). Mechanistic studies confirm the proposed energy transfer pathway and the critical role of the bifunctional design. This work establishes a new paradigm for merging photocatalysis and asymmetric organocatalysis within a single molecule, providing a powerful and practical method for constructing chiral cyclobutane scaffolds, which are privileged structures in medicinal chemistry.

Yulong Cao. Design of Chiral Phosphine Catalysts Driven by Visible Light and Study of Asymmetric [2+2] Cycloaddition Reactions. The Frontiers of Society, Science and Technology (2026), Vol. 8, Issue 1: 13-18. https://doi.org/10.25236/FSST.2026.080103.

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