- Copper-Catalyzed Cyanation of N-Tosylhydrazones with Thiocyanate Salt as the "cN" Source
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A novel protocol for the synthesis of α-aryl nitriles has been successfully achieved via a copper-catalyzed cyanation of N-tosylhydrazones employing thiocyanate as the source of cyanide. The features of this method include a convenient operation, readily available substrates, low-toxicity thiocyanate salts, and a broad substrate scope.
- Huang, Yubing,Yu, Yue,Zhu, Zhongzhi,Zhu, Chuanle,Cen, Jinghe,Li, Xianwei,Wu, Wanqing,Jiang, Huanfeng
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- Palladium-Catalyzed Cross-Coupling of gem-Bis(boronates) with Aryl Halides: An Alternative to Access Quaternary α-Aryl Aldehydes
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The compounds with a quaternary α-aryl aldehyde skeleton are important units in organic chemistry. Previously, the aryl group and carbonyl group are introduced in a stepwise manner. Herein, a novel route is developed to construct the quaternary α-aryl aldehydes with gem-bis(boronates) as precursors, in which the two groups are installed simultaneously. The gem-bis(boronates) are readily available from ketones; as a result, this methodology provides a more general strategy to produce the quaternary α-aryl aldehydes with broad scopes and synthetic convenience.
- Zheng, Purui,Zhai, Yujie,Zhao, Xiaoming,Xu, Tao
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supporting information
p. 393 - 396
(2019/01/23)
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- Regioselective Synthesis of Vinyl Halides, Vinyl Sulfones, and Alkynes: A Tandem Intermolecular Nucleophilic and Electrophilic Vinylation of Tosylhydrazones
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A diazo species is trapped in an intermolecular fashion by two independent ion species in tandem at the carbene center to install an electrophile and a nucleophile on the same carbon. This metal-free concept, which is unprecedented, has been illustrated by regioselective synthesis of a variety of vinyl halides, vinyl sulfones, and alkyne derivatives. (Chemical Equation Presented).
- Ojha, Devi Prasan,Prabhu, Kandikere Ramaiah
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supporting information
p. 18 - 21
(2015/07/28)
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- Unsymmetrical 1,1-diborated multisubstituted sp3-carbons formed via a metal-free concerted-asynchronous mechanism
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We have experimentally proved the unsymmetrical 1,1-diboration of diazo compounds, formed in situ from aldehydes and cyclic and non-cyclic ketones, in the absence of any transition metal complex. The heterolytic cleavage of the mixed diboron reagent, Bpin-Bdan, and the formation of two geminal C-Bpin and C-Bdan bonds has been rationalised based on DFT calculations to occur via a concerted-asynchronous mechanism. Diastereoselection is attained on substituted cyclohexanones and DFT studies provide understanding on the origin of the selectivity. The alkoxide-assisted selective deborylation of Bpin from multisubstituted sp3-carbon and generation of a Bdan stabilized carbanion, easily conducts a selective protodeboronation sequence.
- Cuenca, Ana B.,Cid, Jessica,García-López, Diego,Carbó, Jorge J.,Fernández, Elena
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supporting information
p. 9659 - 9664
(2015/09/28)
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- Preparation of unsymmetrical ketones from tosylhydrazones and aromatic aldehydes via formyl C-H bond insertion
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Preparation of ketones by insertion of diazo compounds into the formyl C-H bond of an aldehyde is an attractive procedure, but use of structurally diverse diazo compounds is hampered by preparation and safety issues. A convenient procedure for the synthesis of unsymmetrical ketones from bench-stable tosylhydrazones and aryl aldehydes is reported. The procedure can be performed in one pot from the parent carbonyl compound and needs only a base, with no additional promoters being required.
- Allwood, Daniel M.,Blakemore, David C.,Ley, Steven V.
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supporting information
p. 3064 - 3067
(2014/06/23)
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- Copper-catalyzed aerobic oxidative transformation of ketone- Derived N-tosyl hydrazones: An entry to alkynes
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A novel strategy involving Cu-catalyzed oxidative transformation of ketone-derived hydrazone moiety to various synthetic valuable internal alkynes and diynes has been developed. This method features inexpensive metal catalyst, green oxidant, good functional group tolerance, high regioselectivity and readily available starting materials. Oxidative deprotonation reactions were carried out to form internal alkynes and symmetrical diynes. Cross-coupling reactions of hydrazones with halides and terminal alkynes were performed to afford functionalized alkynes and unsymmetrical conjugated diynes. A mechanism proceeding through a Cu-carbene intermediate is proposed for the CC triple bond formation.
- Li, Xianwei,Liu, Xiaohang,Chen, Huoji,Wu, Wanqing,Qi, Chaorong,Jiang, Huanfeng
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supporting information
p. 14485 - 14489
(2015/02/05)
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- Copper-catalyzed reductive coupling of tosylhydrazones with amines: A convenient route to α-branched amines
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A general procedure for the reductive coupling of N-tosylhydrazones with amines in the presence of Cu(acac)2 and Cs2CO3 has been developed. The protocol is very effective and chemoselective with various primary and secondary aliphatic amines, aminoalcohols as well as azole derivatives to give α-branched amines in good yields.
- Hamze, Abdallah,Treguier, Bret,Brion, Jean-Daniel,Alami, Mouad
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supporting information; experimental part
p. 6200 - 6204
(2011/10/08)
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- THE REACTION OF α,β-UNSATURATED p-TOSYLHYDRAZONES WITH SULPHUR CHLORIDES
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α,β-Unsaturated p-tosylhydrazones react with tetravalent and divalent sulphur chlorides affording 1,2,3-thiadiazoles in good yields.The necessary methylene group adjacent to the C=N bond may be provided by electrophilic addition of a hydrogen chloride molecule.The major difference in the product distribution in the reactions of unsaturated and saturated p-tosylhydrazones with SOCl2, SCl2 or S2Cl2 is observed with substrates prepared from methyl ketones; on using SOCl2 a more favourable distribution of compounds derived from cyclization on the methyl group is obtained.
- Bellesia, Franco,Grandi, Romano,Pagnoni, Ugo M.,Trave, Roberto
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p. 289 - 292
(2007/10/02)
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