- Visible Light-Catalyzed Benzylic C-H Bond Chlorination by a Combination of Organic Dye (Acr+-Mes) and N-Chlorosuccinimide
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By combining "N-chlorosuccinimide (NCS)"as the safe chlorine source with "Acr+-Mes"as the photocatalyst, we successfully achieved benzylic C-H bond chlorination under visible light irradiation. Furthermore, benzylic chlorides could be converted to benzylic ethers smoothly in a one-pot manner by adding sodium methoxide. This mild and scalable chlorination method worked effectively for diverse toluene derivatives, especially for electron-deficient substrates. Careful mechanistic studies supported that NCS provided a hydrogen abstractor "N-centered succinimidyl radical,"which was responsible for the cleavage of the benzylic C-H bond, relying on the reducing ability of Acr?-Mes.
- Xiang, Ming,Zhou, Chao,Yang, Xiu-Long,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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p. 9080 - 9087
(2020/08/14)
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- Efficient C(sp3)-H bond functionalization of isochroman by azadol catalysis
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A novel organocatalytic C(sp3)-H bond functionalization of isochroman under practical conditions has been developed. In the presence of 5.0 mol % of AZADOL, the catalysis proceeded successfully with a broad range of substrates and nucleophiles in excellent yields.
- Muramatsu, Wataru,Nakano, Kimihiro
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p. 1549 - 1552
(2015/03/30)
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- Dialkyl Ether Formation by Nickel-Catalyzed Cross-Coupling of Acetals and Aryl Iodides
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A new substrate class for nickel-catalyzed C(sp3) cross-coupling reactions is reported. α-Oxy radicals generated from benzylic acetals, TMSCl, and a mild reductant can participate in chemoselective cross-coupling with aryl iodides using a 2,6-bis(N-pyrazolyl)pyridine (bpp)/Ni catalyst. The mild, base-free conditions are tolerant of a variety of functional groups on both partners, thus representing an attractive C-C bond-forming approach to dialkyl ether synthesis. Characterization of a [(bpp)NiCl] complex relevant to the proposed catalytic cycle is also described.
- Arendt, Kevin M.,Doyle, Abigail G.
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supporting information
p. 9876 - 9880
(2015/08/19)
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- Organocatalytic approach for C(sp3)-H bond arylation, alkylation, and amidation of isochromans under facile conditions
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A new catalytic approach for the synthesis of isochroman derivatives via direct C(sp3)-H bond arylation is described. The oxidation reaction with [bis(trifluoroacetoxy)iodo]benzene facilitates the regeneration of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in the C(sp3)-H bond arylation of isochroman. The reaction conditions can also be used for alkyl Grignard reagents and amides to afford the corresponding isochroman derivatives.
- Muramatsu, Wataru,Nakano, Kimihiro
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supporting information
p. 2042 - 2045
(2014/05/06)
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- Simple and direct sp3 C-H bond arylation of tetrahydroisoquinolines and isochromans via 2,3-dichloro-5,6-dicyano-1,4- benzoquinone oxidation under mild conditions
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The 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-mediated sp3 C-H bond arylation of tetrahydroisoquinolines and isochromans is described. The corresponding products were facilely synthesized via a simple nucleophilic addition reaction betwee
- Muramatsu, Wataru,Nakano, Kimihiro,Li, Chao-Jun
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supporting information
p. 3650 - 3653
(2013/08/23)
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- Reactions of diazoalkanes with molybdenum peroxide
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The reactions of diazoalkanes with MoO5·HMPA·H2O caused both oxidation into carbonyl compounds and metal carbenoid insertion reaction with methanol to give methyl alkyl ethers. These reaction paths are affected by the substituent of diazoalkanes.
- Kawasaki, Tomomi,Hoshi, Ryuichi,Yamamoto, Toshihiko,Satoh, Kazue,Sakamoto, Masanori
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p. 565 - 572
(2007/10/03)
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- Kinetics and Mechanism of Reactions of Benzhydryl Chlorides with Anilines
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Nucleophilic substitution reactions of substituted benzhydryl chlorides with anilines in acetonitrile and methanol are investigated.The reactions are found to proceed by the attack of nucleophile on the preformed carbocation, I, within the ion pair.The cr
- Chang, Saemin,Koh, Han Joong,Lee, Bon-Su,Lee, Ikchoon
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p. 7760 - 7768
(2007/10/03)
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- A Relationship between Selectivity and Solvent Composition for Nucleophilic Attack on Carbocations in Alcohol-Water Mixtures
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Rate constants and products of solvolyses of p-methoxybenzyl chloride 1, chlorodiphenylmethane 2 (Y = Z = H), chloro(4-chlorophenyl)phenylmethane 2 (Y = H, Z= Cl) and chlorobis(4-chlorophenyl)methane 2 (Y = Z = Cl) are reported in ethanol- and methanol-water mixtures at 25 deg C.Product selectivities (S), defined by: S = / are related to four rate constants for reactions involving one molecule of solvent as nucleophile and another molecule of solvent as general base catalyst (e.g. kwa involves water as nucleophile and alcohol as general base, and kww, kaw and kaa are defined similarly).A linear relationship between 1/S and molar ratios of solvent 1/S = (kwa/kaw)(/) + kww/kaw is derived theoretically and validated experimentally for solvolyses of the above substrates from water up to 70percent alcohol-water-in this range of solvents, the contribution from kaa can be neglected.For solvolyses of p-methoxybenzyl chloride, S is independent of pH between pH 2 and 12, S decreases when acetone is added but increases if acetonitrile is added and for 90percent ethanol-water S increases with added LiCl and LiClO4 and increases further if acetonitrile is also present.
- Bentley, T. William,Ryu, Zoon Ha
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p. 761 - 768
(2007/10/02)
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- Photolysis of Tetraarylmethanes and 3-(Triarylmethyl)pyridines
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Upon UV irradiation in benzene-methanol (1:2) tetraarylmethanes or 3-(triarylmethyl)pyridines underwent an α,α-elimination of two aryl groups to give biaryls or 3-arylpyridine, and two corresponding carbene intermediates.The latters afforded methyl ethers by O-H insertion to methanol.
- Shi, Min,Okamoto, Yoshiki,Takamuku, Setsuo
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p. 2731 - 2733
(2007/10/02)
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- The Absolute Kinetics of Several Reactions of Substituted Diphenylcarbenes
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4,4'-dibromo-, 4-bromo-, 4,4'-dichloro-, 4-chloro-, 4-methyl-, 4,4'-dimethyl-, 4-phenyl-, 4-carbomethoxyl-, 4-cyano-, 4-cyano-4'-methyl-, and 4,4'-dimethyldiphenyldiazomethane were studied by laser flash photolysis.Excitation of the diazo compounds at 308 nm produced the corresponding diarylcarbenes.The kinetics of the reaction of the substituted carbenes with alkanes and methanol were examined.Hydrogen abstraction rates are largely insensitive to ring substitution, while the methanol reaction is accelerated considerably by p-methyl substitution and retarded by a para electron-withdrawing substituent.
- Hadel, L. M.,Maloney, V. M.,Platz, M. S.,McGimpsey, W. G.,Scaiano, J. C.
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p. 2488 - 2491
(2007/10/02)
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