6942-58-1Relevant articles and documents
Efficient Catalytic Oxidation of Cyclic Acetals with H2O2
Zlotsky, S. S.,Nazarov, M. N.,Kulak, L. G.,Rakhmankulov, D. L.
, p. 441 - 443 (1992)
-
Flavin-functionalized gold nanoparticles as an efficient catalyst for aerobic organic transformations
Imada, Yasushi,Osaki, Motonari,Noguchi, Mikiko,Maeda, Takatoshi,Fujiki, Misa,Kawamorita, Soichiro,Komiya, Naruyoshi,Naota, Takeshi
, p. 99 - 106 (2015/03/04)
Monolayer-protected gold clusters functionalized with synthetic flavins were synthesized and their catalytic activity in aerobic organic transformations investigated. Gold nanoparticles with 5-ethyl-3-(8-thiooctyl)lumiflavinium perchlorate acts as an efficient catalyst for the aerobic oxidation of organic sulfides to the corresponding sulfoxides upon treatment with hydrazine at room temperature and under atmospheric pressure in oxygen. With a catalytic amount of gold nanoparticles with 3-(8-thiooctyl)lumiflavin, diimide reduction of various olefins can be performed with hydrazine at room temperature under atmospheric pressure in air with greater yields of product alkanes than with non-supported 3-methyllumiflavin catalyst under the same conditions. Kinetic studies revealed that the mono-layer-protected gold cluster-catalyzed reactions proceeded faster than those with non-supported catalysts over the full substrate concentration range for the hydrogenation of olefins and at lower substrate concentrations for sulfoxidation. This positive effect was rationalized by assuming a Michaelis-Menten-type mechanism in which the specific inclusion of substrates into the enzyme-like reaction cavities was a key factor in the high efficiency of the supported flavin catalysts.
Aerobic reduction of olefins by in situ generation of diimide with synthetic flavin catalysts
Imada, Yasushi,Iida, Hiroki,Kitagawa, Takahiro,Naota, Takeshi
supporting information; experimental part, p. 5908 - 5920 (2011/07/07)
A versatile reducing agent, diimide, can be generated efficiently by the aerobic oxidation of hydrazine with neutral and cationic synthetic flavin catalysts 1 and 2. This technique provides a convenient and safe method for the aerobic reduction of olefins, which proceeds with 1 equiv of hydrazine under an atmosphere of O2 or air. The synthetic advantage over the conventional gas-based method has been illustrated through high hydrazine efficiency, easy and safe handling, and characteristic chemoselectivity. Vitamin B2 derivative 6 acts as a highly practical, robust catalyst for this purpose because of its high availability and recyclability. Association complexes of 1b with dendritic 2,5-bis(acylamino)pyridine 15 exhibit unprecedented catalytic activities, with the reduction of aromatic and hydroxy olefins proceeding significantly faster when a higher-generation dendrimer is used as a host pair for the association catalysts. Contrasting retardation is observed upon similar treatment of non-aromatic or non-hydroxy olefins with the dendrimer catalysts. Control experiments and kinetic studies revealed that these catalytic reactions include two independent, anaerobic and aerobic, processes for the generation of diimide from hydrazine. Positive and negative dendrimer effects on the catalytic reactions have been ascribed to the specific inclusion of hydrazine and olefinic substrates into the enzyme-like reaction cavities of the association complex catalysts. Copyright