The Rh2(esp)2 and Zn(II)-bisoxazoline (BOX) complex-cocatalyzed asymmetric diamination of in situ generated difluoroenol species with azocarboxamides has been disclosed. This reaction features a formal [3 + 2]-cycloaddition reaction using difluoroenol intermediate as a C2 synthon, providing an efficient and robust approach for the synthesis of difluorinated imidazolidin-2-ones in good yields with high to excellent stereoselectivity (up to 95% ee). This method offers a complementary approach for the direct assembly of chiral difluoromethylene incorporated heterocycles by introducing in situ formed difluoroenol species as a practical C2 synthon rather than using presynthesized gem-difluoroalkenes. With this protocol, further synthetic applications in fluorine chemistry could be envisioned through the strategic interception of difluoroenol via cycloaddition reactions with appropriate partners.

Flavin-dependent enzymes are widespread across all kingdoms of life and nicotinamide coenzymes are common flavoenzyme substrates, performing 2-electron (hydride) oxidation or reduction of the flavin c...

In situ transmission electron microscopy (TEM) provides a means for capturing atomic-resolution micrographs under reactive environments and has been widely employed to identify active site candidates ...

Enantioselective transformations are crucial in various fields, including chemistry, biology, and materials science. Today, the selective production of enantiopure compounds is achieved through asymme...

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Transition metal catalysis is an indispensable tool for organic synthesis that has been harnessed, modulated, and perfected for many decades by careful selection of metal centers and ligands, giving r...

Heme-dependent tyrosine hydroxylases (TyrH) are critical enzymes in catecholamine biosynthesis, yet the role of the substrate’s α-amino group in their monooxygenation mechanism has been unclear. Usin...

Understanding charge transfer in light-driven processes is crucial for optimizing the efficiency and performance of a photocatalyst, as charge transfer directly influences the separation and migration of photogenerated charge carriers and determines the overall reaction rate and product formation. However, achieving this understanding remains challenging in the context of single-atom photocatalysis. This study addresses this gap and investigates an Ag-based single-atom catalyst (Ag1@CNx) in the photocatalytic oxidation of benzyl alcohol to benzaldehyde. Comprehensive characterization was conducted using a battery of diffractive, textural, spectroscopic, and microscopic methods, confirming the catalyst crystallinity, porosity, elemental composition, and atomic dispersion of silver atoms. This material displayed efficient performance in the selective oxidation of benzyl alcohol to benzaldehyde. Density functional theory calculations were used to rationalize the catalyst structure and elucidate the reaction mechanism, unveiling the role of the photogenerated holes in lowering the reaction energy barriers. Time-resolved transient spectroscopic studies were used to monitor the dynamics of photogenerated charges in the reaction, revealing the lifetimes and behaviors of excited states within the catalyst. Specifically, the introduction of silver atoms led to a significant enhancement in the excited state lifetime, which favors the hole-transfer in the presence of the benzyl alcohol. This indicated that the photoexcited carriers were effectively transferred to the reactant, thereby driving the oxidation process in the presence of oxygen. These mechanistic insights are pivotal in spectroscopically elucidating the reaction mechanism and can be practically applied to design single-atom photocatalysts more rationally, targeting materials that combine both rapid reductive quenching and efficient charge transfer to the metal.

Designing catalytic approaches to deliberate and selective C–H activation was listed by Bergman among the “Holy Grails” of synthetic chemistry in 1995, and continues to be a hot topic up to now,...