- Benzene C-H Etherification via Photocatalytic Hydrogen-Evolution Cross-Coupling Reaction
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Aryl ethers can be constructed from the direct coupling between the benzene C-H bond and the alcohol O-H bond with the evolution of hydrogen via the synergistic merger of photocatalysis and cobalt catalysis. Utilizing the dual catalyst system consisting of 3-cyano-1-methylquinolinum photocatalyst and cobaloxime, intermolecular etherification of arenes with various alcohols and intramolecular alkoxylation of 3-phenylpropanols with formation of chromanes are accomplished. These reactions proceed at remarkably mild conditions, and the sole byproduct is equivalent hydrogen gas.
- Zheng, Yi-Wen,Ye, Pan,Chen, Bin,Meng, Qing-Yuan,Feng, Ke,Wang, Wenguang,Wu, Li-Zhu,Tung, Chen-Ho
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supporting information
p. 2206 - 2209
(2017/05/12)
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- Methylation of phenol and its derivatives with dimethyl carbonate in the presence of Mn2(CO)10, W(CO)6, and Co2(CO)8
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Aryl methyl ethers were synthesized by reactions of phenol, substituted phenols, and α- and β-naphthols with dimethyl carbonate in the presence of manganese, tungsten, and cobalt carbonyls. Optimal reactant and catalyst ratios and reaction conditions were found to ensure selective formation of aryl methyl ethers.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
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p. 330 - 334
(2015/05/04)
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- SELECTIVE HYDROLYSIS AND ALCOHOLYSIS OF CHLORINATED BENZENES
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The present invention relates to a process for providing a compound of formula (I):, wherein R is hydrogen or R', wherein R' is –(C1-C4)alkyl, and Hal is a halogen, the process comprising the step of: reacting a compound of formula (II) wherein Hal is defined as above, with an alkali metal alkoxide of the formula XOR', wherein X is an alkali metal, and R' is defined as above.
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Page/Page column 15
(2015/04/22)
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- PROCESS FOR HYDROLYZING 1,2,4-TRIHALOBENZENE
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The present invention relates to a process for providing a compound of formula (I): wherein Hal is a halogen, the process comprising the step of: reacting a compound of formula (II) wherein Hal is defined as above, with an alkali metal sulfite of the formula X2SO3 and an alkali metal hydroxide of the formula YOH, wherein X and Y are independently selected from an alkali metal.
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Page/Page column 11
(2015/04/22)
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- The α-effect in methyl transfers from S-methyldibenzothiophenium fluoroborate to substituted N-methylbenzohydroxamates
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Studies of the α-effect show increased reactivity of nucleophiles having lone pairs of electrons on atoms neighboring the lone pair involved in reactivity when compared to the basicity of the nucleophiles. Hammett-type plots and Broensted-type plots of substituted methylphenyl sulfates vs hydrogen peroxide anions and substituted N-methylbenzohydroxanates (NMBH) with substituted methylarenesulfonates or substituted arenedimethylsulfonium ions have large ρ or βnuc values, indicating a putative tightening of the usual SN2 transition states (anti-Hammond effect). Electrochemical studies of SN2-SET or reactivity indicate that SET character occurs in looser transition states, whereas SN2 transition states are associated with greater tightness. The α-effects for the series of sulfonium salts in completion reactions for 3-ClNMBH anions and 3-nitrophenolate anions are (log kα/knormal) 1.124 for dimethylphenyl sulfonium, 1.512 for dimethyl-1-naphthyl sulfonium, 1.835 for dimethyl-9-anthracenyl sulfonium, and 1.137 for S-methyldibenzylthiophenium. Correlations of the sizes of α-effects with typical SET (or ET) experimental parameters and the inverse dependence of the size of the α-effect on electron demand indicate inclusion of SET character in these SN2 transition states, vs no (or at least diminished) SET character in normal transition states. This dichotomy of tighter SN2 transition states, but looser SET transition states indicated in the α-effect, is examined in the present work.
- Fountain,Felkerson, Cassie J.,Driskell, Jeremy D.,Lamp, Brian D.
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p. 1810 - 1814
(2007/10/03)
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