35923-45-6Relevant articles and documents
Aerobic oxygenation of α-methylene ketones under visible-light catalysed by a CeNi3complex with a macrocyclic tris(salen)-ligand
Fujiwara, Sakiko,Kon, Yoshihiro,Mashima, Kazushi,Nagae, Haruki,Okuda, Jun,Sakamoto, Kazutaka,Sato, Kazuhiko,Schindler, Tobias
, p. 11169 - 11172 (2021/11/04)
A hetero-tetranuclear CeNi3 complex with a macrocyclic ligand catalysed the aerobic oxygenation of a methylene group adjacent to a carbonyl group under visible-light radiation to produce the corresponding α-diketones. The visible-light induced homolysis of the Ce-O bond of a bis(enolate) intermediate is proposed prior to aerobic oxygenation.
Rhodium-Catalyzed Aerobic Decomposition of 1,3-Diaryl-2-diazo-1,3-diketones: Mechanistic Investigation and Application to the Synthesis of Benzils
Zhu, Jia-Liang,Tsai, Yi-Ting
, p. 813 - 828 (2020/12/22)
The conversion of 1,3-diaryl-2-diazo-1,3-diketones to 1,2-daryl-1,2-diketones (benzils) is reported based on a rhodium(II)-catalyzed aerobic decomposition process. The reaction occurs at ambient temperatures and can be catalyzed by a few dirhodium carboxylates (5 mol %) under a balloon pressure of oxygen. Moreover, an oxygen atom from the O2 reagent is shown to be incorporated into the product, and this is accompanied by the extrusion of a carbonyl unit from the starting materials. Mechanistically, it is proposed that the decomposition may proceed via the interaction of a ketene intermediate resulting from a Wolff rearrangement of the carbenoid, with a rhodium peroxide or peroxy radical species generated upon the activation of molecular oxygen. The proposed mechanism has been supported by the results from a set of controlled experiments. By using this newly developed strategy, a large array of benzil derivatives as well as 9,10-phenanthrenequinone were synthesized from the corresponding diazo substrates in varying yields. On the other hand, the method did not allow the generation of benzocyclobutene-1,2-dione from 2-diazo-1,3-indandione because of the difficulty of inducing the initial rearrangement.
Lanthanide complexes based on an anthraquinone derivative ligand and applications as photocatalysts for visible-light driving photooxidation reactions
Zhu, Ting-Ting,Tao, Yu-Tong,Sun, Yue,Wang, Xue,Zhang, Xiao-Wen,Chai, Jia-Lu,Han, Jie,Zhao, Xiao-Li,Chen, Xu-Dong
, (2021/04/05)
Four isostructural lanthanide coordination complexes based on 3,7-diamino-9,10-anthraquinone-2,6-disulfonate (dianionic, L) have been synthesized by hydrothermal method, namely [Er(L)(H2O)6]?[Er(H2O)8]?2L?8H2O (Er-L), [Tm(L)(H2O)6]?[Tm(H2O)8]?2L?8.5H2O (Tm-L), [Yb(L)(H2O)6]?[Yb(H2O)8]?2L?9H2O (Yb-L), [Lu(L)(H2O)6]?[Lu(H2O)8]?2L?9H2O (Lu-L). Single-crystal X-ray analysis reveals the existence of both coordinated and free ligand L in the crystal structure. Versatile sulfonate groups on these distinct L ligands, together with very rich coordinated and lattice water molecules, form a lot of hydrogen-bonding motifs that contribute to the stabilization of the crystal packing. It is interesting that the ligands stack into columns through strong π-π interactions and the centroid-centroid distances are between 3.281 and 3.331 ?. These ligands are stacked in an alternate off-set mode to avoid the steric hindrance between the bulky sulfonate groups, generating a repeated structural unit involving six stacked ligands. These lanthanide complexes proved to be good heterogeneous photocatalyst for promoting the visible-light driving photooxidation reactions of diarylacetylenes and thioethers. The Er-L complex exhibited the best catalytic activity and showed good catalytic efficiency over a wide range of substrates for both reaction systems. The Er-L photocatalyst can be easily isolated by simple filtration as crystalline material upon completion of the photooxidation reaction without structure change, and can be recycled for at least five catalytic cycles with persistent catalytic efficiency without any need of activation or regeneration. This family of lanthanide complexes represent a category of promising heterogeneous photocatalysts in terms of green chemistry, with the potential of promoting organic transformations highly efficiently under the irradiation of visible light.
