502-44-3Relevant articles and documents
Selective Aerobic Oxidation of Secondary C (sp3)-H Bonds with NHPI/CAN Catalytic System
Wang, Lingyao,Zhang, Yuanbin,Yuan, Haoran,Du, Renfeng,Yao, Jia,Li, Haoran
, p. 1663 - 1669 (2020/10/21)
Abstract: The direct aerobic oxidation of secondarty C(sp3)-H bonds was achieved in the presence of N-hydroxyphthalimide (NHPI) and cerium ammonium nitrate (CAN) under mild conditions. Various benzylic methylenes could be oxidized to carbonyl compounds in satisfied selectivity while saturated cyclic alkanes could be further oxidized to the corresponding lactones with the catalytic system. Remarkably, 25% of isochroman was converted to corresponding ketone with a selectivity of 96%. The reaction was initiated by hydrogen atom abstraction from NHPI by cerium and nitrates under oxygen atmosphere to form PINO radicals. 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) addition experiments showed that the oxidation proceeded via a complex radical chain mechanism and an ion pathway. Graphic Abstract: [Figure not available: see fulltext.]
Revisiting Alkane Hydroxylation with m-CPBA (m-Chloroperbenzoic Acid) Catalyzed by Nickel(II) Complexes
Itoh, Mayu,Itoh, Shinobu,Kubo, Minoru,Morimoto, Yuma,Shinke, Tomoya,Sugimoto, Hideki,Wada, Takuma,Yanagisawa, Sachiko
, p. 14730 - 14737 (2021/09/29)
Mechanistic studies are performed on the alkane hydroxylation with m-CPBA (m-chloroperbenzoic acid) catalyzed by nickel(II) complexes, NiII(L). In the oxidation of cycloalkanes, NiII(TPA) acts as an efficient catalyst with a high yield and a high alcohol selectivity. In the oxidation of adamantane, the tertiary carbon is predominantly oxidized. The reaction rate shows first-order dependence on [substrate] and [NiII(L)] but is independent on [m-CPBA]; vobs=k2[substrate][NiII(L)]. The reaction exhibited a relatively large kinetic deuterium isotope effect (KIE) of 6.7, demonstrating that the hydrogen atom abstraction is involved in the rate-limiting step of the catalytic cycle. Furthermore, NiII(L) supported by related tetradentate ligands exhibit apparently different catalytic activity, suggesting contribution of the NiII(L) in the catalytic cycle. Based on the kinetic analysis and the significant effects of O2 and CCl4 on the product distribution pattern, possible contributions of (L)NiII?O. and the aroyloxyl radical as the reactive oxidants are discussed.
Kinetics Modeling of a Convergent Cascade Catalyzed by Monooxygenase-Alcohol Dehydrogenase Coupled Enzymes
Bornscheuer, Uwe T.,Engel, Jennifer,Kara, Selin
supporting information, p. 411 - 420 (2020/12/22)
A convergent cascade reaction coupling a cyclohexanone monooxygenase variant and an alcohol dehydrogenase to make ?-caprolactone from cyclohexanone and 1,6-hexanediol was characterized via progress curve analysis with two kinetic models developed iteratively. A chemical side reaction occurring with the utilized Tris buffer and consequent byproduct formations were considered in Model 2, which reduced the root-mean-square error (RMSE) values by half, compared to Model 1 (RMSE values of 13%-40%). The optimized model, Model 2, led us to simulate the cascade reaction including 22 kinetic parameters with a maximum RMSE value in the range of 10%-21%.