Carbocation catalysis can be performed inside the confined space of the hexameric resorcinarene capsule. The inner cavity of the capsule can host the trityl carbocation, which catalyses the Diels-Alder reaction between dienes and unsaturated aldehydes. Experimental results and calculations show that the hexameric resorcinarene capsule C can promote the formation of the trityl carbocation from trityl chloride through the cleavage of the carbon-halogen bond promoted by OH⋯X hydrogen bonding. Here it is shown that the combination of the nanoconfined space and the latent carbocation catalysis provides a convenient complementary strategy for the typical carbocation catalysis. The latent strategy bypasses the typical pitfalls associated with active carbocations and provides control of the reaction efficiency in terms of reaction rate, conversion, and selectivity.
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http://dx.doi.org/10.1039/d2sc02901d | DOI Listing |
Angew Chem Int Ed Engl
December 2024
Department of chemistry, University of California, Riverside, Riverside, CA, 92521, USA.
Sulfated zirconium oxide (SZO) catalyzes the hydrogenolysis of isotactic polypropylene (iPP, M=13.3 kDa, Đ=2.4,
Org Lett
December 2024
Jiangsu Provincial Key Lab for the Chemistry and Utilization of Agro-Forest Biomass, Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Jiangsu Key Lab of Biomass-Based Green Fuels and Chemicals, International Innovation Center for Forest Chemicals and Materials, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, Jiangsu, China.
Chemistry
November 2024
Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, No. 381, Wushan Road, Tianhe district, Guangzhou, 510641, China.
α-Diazoesters belong to significantly important carbenoid precursors in synthetic chemistry. Diazomethylation-based difunctionalization of alkenes is highly valuable but remain nontrivial. Herein, we reported a general and modular approach for the direct 1,2-oxydiazomethylation of alkenes through visible-light photoredox catalysis.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
We report the photocatalytic oxidation of α-carbonyl radicals of amides or esters to the corresponding α-carbonyl carbocations through super photoreductant CBZ6 induced redox-neutral photocatalysis. The α-carbonyl radicals are formed by the β-addition of alkyl radicals generated in situ by the photocatalytic fragmentation of N-hydroxyphthalimide esters to the α,β-unsaturated amides and esters. This method enables the α-nucleophilic addition of hydroxyl or alkoxyl radicals to amides and esters without any prefunctionalization.
View Article and Find Full Text PDFOrg Lett
October 2024
Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building Park Place, Cardiff, CF10 3AT, United Kingdom.
Herein we report an electrochemical deconstructive functionalization approach for the synthesis of C(sp)-rich heterocycles. The reaction proceeds the mesolytic cleavage of anodically generated aromatic radical cations and the trapping of formed carbocation intermediates with internal nucleophiles. The method has been demonstrated across various arylalcohol substrates to access a diverse range of C(sp)-rich heterocycles including tetrahydrofuran, tetrahydropyran, and pyrrolidine scaffolds (26 examples).
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