3128-07-2Relevant articles and documents
Mixed crystals containing the dioxo complex [{Ph3SiO} 2VO2]- and novel pentacoordinated oxoperoxo complex [{Ph3SiO}2- VO(O2)]-: X-ray crystal structure and assessment as oxidation catalysts
Vennat, Maxence,Bregeault, Jean-Marie,Herson, Patrick
, p. 908 - 913 (2004)
[n-Bu4N][{Ph3SiO}2VO2] reacts with H2O2 tomixed-crystal yield an oxoperoxo complex which crystallizes as a mixed-crystal compound, [P(C6H5) 4][{(C6H5)3 SiO}2VO 2]x[{(C6H5)3 SiO} 2VO(O2)]1-x, 1 (x = 0.57). It has been characterized by elemental analysis and spectroscopy (51V NMR, UV-visible and IR). The X-ray structure analysis reveals the presence of two interrelated anions: [{Ph3SiO}2VvO 2]-, 1a, and [{Ph3SiO}2V vO(O2)]-, 1b with a cisoid geometry of the (VO(O2)}+ moiety. The two structures differ only slightly: anion 1a exhibits unusual tetrahedral coordination around the vanadium centre found in the precursor, whereas the geometry at the metal ion in 1b can be described as a trapezoidal pyramid. Steric constraints due to Ph 3SiO- ligands and PPh4+ cations are responsible for this geometry. The reactivity of 1 in the C-C bond cleavage of 2-methylcyclohexanone under anaerobic conditions has been studied. The results suggest that peroxygen species are involved in the oxidative cleavage of C-C bonds of cycloalkanones.
Azolium/Hydroquinone Organo-Radical Co-Catalysis: Aerobic C?C-Bond Cleavage in Ketones
Nakatsuji, Yuya,Kobayashi, Yusuke,Masuda, Sakyo,Takemoto, Yoshiji
supporting information, p. 2633 - 2637 (2021/02/03)
Organo-radical catalysts have recently attracted great interest, and the development of this field can be expected to broaden the applications of organocatalysis. Herein, the first example of a radical-generating system is reported that does not require any photoirradiation, radical initiators, or preactivated substrates. The oxidative C?C-bond cleavage of 2-substituted cyclohexanones was achieved using an azolium salt and a hydroquinone as co-catalysts. A catalytic mechanism was proposed based on the results of diffusion-ordered spectroscopy and cyclic voltammetry measurements, as well as computational studies.
Catalytic oxidation of α-substituted cyclohexanone with steric hindrance to 6-oxohexanoic acid involved during the total synthesis of (+)-biotin
Li, Haoran,Ma, Qiyi,Mao, Jianyong,Yao, Jia,Yuan, Haoran
, (2021/08/13)
A homogeneous catalyst system FeCl3/DMSO was developed to catalyze α-substituted cyclohexanone to corresponding 6-oxohexanoic acid, an important intermediate involved during the synthesis of (+)-biotin. A highly efficient oxidation with 95.3 % of conversion and 88.0 % of selectivity was achieved using oxygen as the oxidant, which shows great advantage over the traditional peroxide method from industrial aspects. The detailed reaction process was evaluated to determine the parallel reactions scheme consisted by two oxidative reactions and one chlorination reaction. The [Fe(DMSO)4Cl2]Cl complex detected by UV–vis and FT-IR spectrometer was proposed as the active component during the catalytic process. The control experiments, capture of important intermediates, and kinetic study were performed, which showed the oxidation proceeded via the combination of ionic and radical pathway. The FeCl3/DMSO can be recycled with minor yield loss.
