Stereospecific Photoredox-Catalyzed Vinylations to Functionalized Alkenes and C-Glycosides**

We report an efficient radical-mediated C−C coupling through photoredox-catalyzed reactions of 4-alkyl-dihydropyridines (DHPs) and vinylbenziodoxol(on)es (VBX, VBO). This transition-metal-free and mild photocatalytic method has excellent functional group tolerance and affords vinylated products in good yields, with complete retention of the alkene configuration. The utility of the methodology is demonstrated by the diastereoselective synthesis of C-vinyl glycosides. Preliminary mechanistic studies suggest that the C−C bond formation is stereospecific and proceeds through a concerted radical coupling transition state.     

Porous Salts Containing Cationic Al24-Hydroxide-Acetate Clusters from Scalable,Green and Aqueous Synthesis Routes

The solution chemistry of aluminum is highly complex and various polyoxocations are known. Here we report on the facile synthesis of a cationic Al₂₄ cluster that forms porous salts of composition [Al₂₄(OH)₅₆(CH₃COO)₁₂]X₄, denoted CAU-55-X, with X=Cl⁻, Br⁻, I⁻, HSO₄⁻. Three-dimensional electron diffraction was employed to determine the crystal structures. Various robust and mild synthesis routes for the chloride salt [Al₂₄(OH)₅₆(CH₃COO)₁₂]Cl₄ in water were established resulting in high yields (>95 %, 215 g per batch) within minutes. Specific surface areas and H₂O capacities with maximum values of up to 930 m² g⁻¹ and 430 mg g⁻¹ are observed. The particle size of CAU-55-X can be tuned between 140 nm and 1250 nm, permitting its synthesis as stable dispersions or as highly crystalline powders. The positive surface charge of the particles, allow fast and effective adsorption of anionic dye molecules and adsorption of poly- and perfluoroalkyl substances (PFAS).