34672-84-9Relevant articles and documents
Enantioselective synthesis of epoxides having a tetrasubstituted trifluoromethylated carbon center: Methylhydrazine-induced aerobic epoxidation of β,β-disubstituted enones
Kawai, Hiroyuki,Okusu, Satoshi,Yuan, Zhe,Tokunaga, Etsuko,Yamano, Akihito,Shiro, Motoo,Shibata, Norio
, p. 2221 - 2225 (2013)
The unprecedented title reaction is catalyzed by a methylhydrazine/base/ organocatalyst (1) system. Biologically attractive epoxides (2) having a tetrasubstituted trifluoromethylated carbon center were obtained with excellent enantioselectivity for the first time. 18O-labeling experiments suggest a mechanism involving the activation of molecular oxygen. MTBE=methyl tert-butyl ether. Copyright
Selective Si-C bond cleavage on a diorganosilicon porphyrin complex bearing different axial ligands
Ishida, Shintaro,Yoshimura, Kimio,Matsumoto, Hideyuki,Kyushin, Soichiro
, p. 362 - 363 (2009)
Tetraphenylporphyrinato methylphenylsilicon complex (abbreviated to Si(TPP)MePh) was synthesized and structurally characterized. Although the Si-Ph bond of Si(TPP)MePh is much longer than the Si-Me bond, photolysis and chemical oxidation of Si(TPP)MePh cl
Visible-light-promoted catalyst-/additive-free synthesis of aroylated heterocycles in a sustainable solvent
Zeng, Fan-Lin,Xie, Kun-Chen,Liu, Yu-Ting,Wang, He,Yin, Peng-Cheng,Qu, Ling-Bo,Chen, Xiao-Lan,Yu, Bing
, p. 1732 - 1737 (2022/03/07)
A general visible-light-induced catalyst-/additive-free strategy was developed for the construction of various aroylated heterocycles (55 examples, up to 95% yield, including modification of pharmaceuticals and natural products) such as thioflavones, benzimidazo[2,1-a]isoquinolin-6(5H)-ones, indolo[2,1-a]isoquinolin-6(5H)ones, quaternary 3,3-dialkyl 2-oxindoles, quinoxalin-2(1H)-ones, and benzo[e][1,2,3]oxathiazine 2,2-dioxides in a green solvent (dimethyl carbonate) under air and room temperature conditions. This practical acylation process was achieved using 4-acyl-1,4-dihydropyridines (acyl-DHPs) as acylating reagents under mild conditions, avoiding the use of catalysts, bases, additional oxidants, and traditional organic solvents. This journal is
Non-Heme-Iron-Mediated Selective Halogenation of Unactivated Carbon?Hydrogen Bonds
Bleher, Katharina,Comba, Peter,Faltermeier, Dieter,Gupta, Ashutosh,Kerscher, Marion,Krieg, Saskia,Martin, Bodo,Velmurugan, Gunasekaran,Yang, Shuyi
supporting information, (2021/12/09)
Oxidation of the iron(II) precursor [(L1)FeIICl2], where L1 is a tetradentate bispidine, with soluble iodosylbenzene (sPhIO) leads to the extremely reactive ferryl oxidant [(L1)(Cl)FeIV=O]+ with a cis disposition of the chlorido and oxido coligands, as observed in non-heme halogenase enzymes. Experimental data indicate that, with cyclohexane as substrate, there is selective formation of chlorocyclohexane, the halogenation being initiated by C?H abstraction and the result of a rebound of the ensuing radical to an iron-bound Cl?. The time-resolved formation of the halogenation product indicates that this primarily results from sPhIO oxidation of an initially formed oxido-bridged diiron(III) resting state. The high yield of up to >70 % (stoichiometric reaction) as well as the differing reactivities of free Fe2+ and Fe3+ in comparison with [(L1)FeIICl2] indicate a high complex stability of the bispidine-iron complexes. DFT analysis shows that, due to a large driving force and small triplet-quintet gap, [(L1)(Cl)FeIV=O]+ is the most reactive small-molecule halogenase model, that the FeIII/radical rebound intermediate has a relatively long lifetime (as supported by experimentally observed cage escape), and that this intermediate has, as observed experimentally, a lower energy barrier to the halogenation than the hydroxylation product; this is shown to primarily be due to steric effects.
Ultrafine Copper Oxide Particles Dispersed on Nitrogen-Doped Hollow Carbon Nanospheres for Oxidative Esterification of Biomass-Derived 5-Hydroxymethylfurfural
Gupta, Shyam Sunder R.,Vinu, Ajayan,Kantam, Mannepalli Lakshmi
, p. 259 - 269 (2021/03/01)
One-pot synthesis of furan-2,5-dimethylcarboxylate (FDMC) from 5-hydroxymethylfurfural (HMF) is highly demanding for the commercial production of polyethylene furanoate (PEF). Herein, a direct synthesis of FDMC is reported from oxidative esterification of HMF using ultrafine CuO particles dispersed on nitrogen-doped hollow carbon nanospheres (CuO/N?C?HNSs) as a catalyst and tert-butyl hydroperoxide (TBHP) as an oxidizing and methylating reagent. The CuO/N?C?HNSs was prepared through a template protection-sacrifice strategy using SiO2 as a sacrificial template and histidine as the precursor for N and C. N-doping facilitated a strong interaction between the support and copper species, affording formation of CuO nanoparticles of less than 10 nm in size. By virtue of the highly dispersed CuO nanoparticles and a high BET surface area 373 m2/g, the CuO/N?C?HNSsshows excellent catalytic performance in the selective conversion of HMF into FDMC affording 93 % yield of the desired product with a TON value of 49. Furthermore, the oxidative esterification involving SP3C?H bond functionalization is also demonstrated using the same catalyst.
