Rhodium-catalyzed intramolecular cyclization for synthesizing thiodihydropyrans.

Addressing the challenge of constructing multi-substituted dihydropyrans, we present an efficient synthesis method for oxygen-containing heterocycles. Using thiones and metal carbenes, we employed xanthate and triazole to intramolecularly synthesize dihydropyran or dihydrofuran compounds. 1,2-Hydride migration was inhibited, and thiodihydropyrans were obtained in excellent yields. A mechanism proceeding through a Rh-carbene intermediate is proposed for the multi-substituted dihydropyrans synthesis.

Copper-Catalyzed Synthesis of Furan-Tethered Benzocyclobutenes via Carbene-Mediated 1,4-Sulfinate Migration-Annulation.

A copper-catalyzed intramolecular cascade reaction of conjugated enynones has been achieved via a pivotal 1,4-sulfinate migration step. This process leverages a cost-effective and ecofriendly copper salt as catalyst, enabling the efficient construction of five- and four-membered rings in a rapid, sequential manner, producing furan-tethered benzocyclobutenes in good to excellent yields under mild conditions. The reaction is characterized by 100% atom economy, outstanding efficiency, and excellent diastereoselectivity in the cases studied. The robustness of this method is evidenced by its compatibility with air exposure and the use of undistilled, commercially available solvents, further enhancing its practicality.

Aerobic Oxysulfonylation of Olefins Using N-Sulfonylaminophthalimides as Sulfonyl Radical Precursors.

Readily accessible N-sulfonylaminophthalimides were developed to be efficient sulfonyl radical precursors upon being treated with a base/oxidant under mild conditions. The method was applied to the oxysulfonylation of olefins, providing ß-ketosulfones and isobenzofurans stereoselectively. On the basis of control experiments, density functional theory calculations, and the literature, a plausible radical mechanism was proposed. The findings offered a chance to develop novel radical precursors based on diversely substituted N-aminophthalimides, which might establish a universal mild approach for the generation of various radicals.

Fe-TiO2-x/TiO2 S-scheme homojunction for efficient photocatalytic CO2 reduction.

CO2-to-high value-added chemicals via a photocatalytic route is of interest but strangled by the low efficiency. Herein, a novel Fe-TiO2-x/TiO2 S-scheme homojunction was designed and constructed by using a facile surface modification approach whereby oxygen vacancy (OV) and Fe introducing on the TiO2 nanorod surface. The as-synthesized Fe-TiO2-x/TiO2 S-scheme homojunction exhibits positive properties on promoting photocatalytic CO2 reduction: i) the nanorod structure provides numerous active sites and a radical charge transfer path; ii) the doped Fe and OV not only synergistically enhance light utilization but also promote CO2 adsorption; iii) the Fe-TiO2-x/TiO2 S-scheme homojunction benefits photoexcited charge separation and retains stronger redox capacity. Thanks to those good characters, the Fe-TiO2-x/TiO2 homojunction exhibits superior CO2 reduction performances with optimized CO/CH4 generation rates of 122/22 µmol g-1h-1 which exceed those of pure TiO2 by more than 9.4/7.3 folds and most currently reported catalytic systems. This manuscript develops a facile and universal approach to synthesize well-defined homojunction and may inspire the construction of other more high-efficiency photocatalysts toward CO2 reduction and beyond.