In recent years, photocycloaddition reactions mediated by Dexter energy transfer under visible light have offered a distinctive platform for dearomatization. Nevertheless, such reactions are currently dominated by dearomatizing cycloadditions between excited-state aromatics and ground-state non-photoactive alkenes. In contrast, dearomatizing cycloadditions involving ground-state non-photoactive aromatics and excited-state photoactive alkenes remain largely underdeveloped. Moreover, the high reactivity and short lifetime of radicals render the enantioinduction of photocatalytic asymmetric dearomatization extremely challenging. Additionally, although metal-organic cages have demonstrated promising catalytic performance as enzyme-mimetic catalysts, their applications in asymmetric photocatalysis are still quite limited.
Recently, a research team led by Prof. Cheng-Yong Su and Peng Hu from Sun Yat-sen University, Chinareported the intermolecular asymmetric dearomatizing photocycloaddition of (benzo)furans with excited-state alkenes catalyzed by chiral metal-organic cages. The results were published in Chinese Journal of Catalysis (DOI: 10.1016/S1872-2067(26)65001-2) .
This work verified via Stern-Volmer quenching, UV–vis absorption spectroscopymeasurements, and control experiments that chiral metal–organic cages Δ/Λ-MOC-16 catalyze intermolecular photocycloaddition between ground-state aromatics and excited-state photoactive alkenes to accomplish asymmetric dearomatization. ¹H NMR titration and solubilization experiments further demonstrated that the chiral confined microenvironment within the cage enables selective dynamic encapsulation of substrates. Such encapsulation improves substrate proximity and local concentration, dictates the relative orientation of bound substrates, and restricts the molecular geometry and free diffusion of excited-state substrates, thereby enabling precise control over the reaction's regioselectivity, diastereoselectivity, and enantioselectivity.
The reaction exhibited broad substrate generality, tolerating cinnamate and (benzo)furan substrates bearing substituents with varied electronic properties, substitution positions, and steric hindrance, furnishing a diverse library of three-dimensional fused polycyclic skeletons with up to 98% yield, >20:1 d.r., and 99% ee. Additionally, derivatization transformations including epimerization, ring-opening reactions, Suzuki–Miyaura coupling, and Sonogashirareactionwere successfully performed on the cycloadducts, highlighting the synthetic utility of this catalytic strategy.
About the Journal
Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top one journals in Applied Chemistry with a current SCI impact factor of 17.2. The Editors-in-Chief are Profs. Can Li and Tao Zhang.
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