- A Mononuclear Non-Heme Manganese(III)-Aqua Complex in Oxygen Atom Transfer Reactions via Electron Transfer
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Metal-oxygen complexes, such as metal-oxo [M(O2-)], -hydroxo [M(OH-)], -peroxo [M(O22-)], -hydroperoxo [M(OOH-)], and -superoxo [M(O2?-)] species, are capable of conducting oxygen atom transfer (OAT) reactions with organic substrates, such as thioanisole (PhSMe) and triphenylphosphine (Ph3P). However, OAT of metal-aqua complexes, [M(OH2)]n+, has yet to be reported. We report herein OAT of a mononuclear non-heme Mn(III)-aqua complex, [(dpaq)MnIII(OH2)]2+ (1, dpaq = 2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8-yl-acetamidate), to PhSMe and Ph3P derivatives for the first time; it is noted that no OAT occurs from the corresponding Mn(III)-hydroxo complex, [(dpaq)MnIII(OH)]+ (2), to the substrates. Mechanistic studies reveal that OAT reaction of 1 occurs via electron transfer from 4-methoxythioanisole to 1 to produce the 4-methoxythioanisole radical cation and [(dpaq)MnII(OH2)]+, followed by nucleophilic attack of H2O in [(dpaq)MnII(OH2)]+ to the 4-methoxythioanisole radical cation to produce an OH adduct radical, 2,4-(MeO)2C6H3S?(OH)Me, which disproportionates or undergoes electron transfer to 1 to yield methyl 4-methoxyphenyl sulfoxide. Formation of the thioanisole radical cation derivatives is detected by the stopped-flow transient absorption measurements in OAT from 1 to 2,4-dimethoxythioanisole and 3,4-dimethoxythioanisole, being compared with that in the photoinduced electron transfer oxidation of PhSMe derivatives, which are detected by laser-induced transient absorption measurements. Similarly, OAT from 1 to Ph3P occurs via electron transfer from Ph3P to 1, and the proton effect on the reaction rate has been discussed. The rate constants of electron transfer from electron donors, including PhSMe and Ph3P derivatives, to 1 are fitted well by the electron transfer driving force dependence of the rate constants predicted by the Marcus theory of outer-sphere electron transfer.
- Sharma, Namita,Zou, Huai-Bo,Lee, Yong-Min,Fukuzumi, Shunichi,Nam, Wonwoo
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p. 1521 - 1528
(2021/02/01)
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- Electrochemical and direct C-H methylthiolation of electron-rich aromatics
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The electrochemical-induced C-H methylthiolation of electron-rich aromatics has been accomplished via a three component cross-coupling strategy. Potassium thiocyanate (KSCN) as both the supporting electrolyte and sulfur source and methanol as the methylation reagent are used. This protocol is versatile for various (hetero)aromatic compounds such as aniline, anisole and indole. The reaction proceeds under mild conditions without any metal catalyst, exogenous oxidant and highly toxic sulfur reagent. Importantly, such an electrochemical-induced methylthiolated reaction could be easily scaled up with good efficiency.
- Wu, Yaxing,Ding, Hongliang,Zhao, Ming,Ni, Zhong-Hai,Cao, Jing-Pei
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supporting information
p. 4906 - 4911
(2020/08/25)
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- Automated synthesis of backbone protected peptides
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The synthesis of peptides rich in aggregation prone sequences can be improved with backbone protection. We report the automated introduction of backbone protection to a peptide. This new method was applied in a fully-automated synthesis, giving improved handling, quality and yield of several challenging target sequences. This journal is the Partner Organisations 2014.
- Abdel-Aal, Abu-Baker M.,Papageorgiou, George,Quibell, Martin,Offer, John
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supporting information
p. 8316 - 8319
(2014/07/22)
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- Regioselective SNAr reactions of substituted difluorobenzene derivatives: practical synthesis of fluoroaryl ethers and substituted resorcinols
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In this Letter, we describe a practical and highly selective method for the preparation of fluoroaryl ethers and differentially substituted resorcinol derivatives. This synthetic strategy relies on a selective SNAr of substituted difluorobenzen
- Ouellet, Stéphane G.,Bernardi, Anna,Angelaud, Remy,O'Shea, Paul D.
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supporting information; experimental part
p. 3776 - 3779
(2009/10/11)
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- An Efficient Synthesis of Unsymmetrical Sulfides from Organic Disulfides and Aromatic Compounds
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In the presence of an active acidic catalyst generated from SbCl5 and AgSbF6, the sulfenylation reaction of aromatic compounds with organic disulfides smoothly proceeds in refluxing 1,2-dichloroethane to afford the corresponding unsymmetrical sulfides in high yields.
- Mukaiyama, Teruaki,Suzuki, Kaoru
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- Monomethylthio analogues of 1-(2,4,5-trimethoxyphenyl)-2-aminopropane
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Regiospecific syntheses of the three monomethylthio analogues of 1-(2,4,5- trimethoxyphenyl)-2-aminopropane are described. The three isomeric amines were evaluated for potential psychotomimetic potency using the rabbit hyperthermia assay. Enantiomeric com
- Jacob III,Anderson III,Meshul,Shulgin,Castagnoli Jr.
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p. 1235 - 1239
(2007/10/06)
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