- Iodosobenzene diacetate-Iodine and IBX-Iodine: Reagent systems for the synthesis of diastereomerically enriched 2-deoxy-2-iodoglycosyl acetates and 2-deoxy-2-iodoglycosyl ortho-iodobenzoates from protected glycals
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Two efficient, metal free reagent systems, PhI(OAc)2-I2 (method A) and IBX-I2 (method B), for stereoselective synthesis of trans-2-deoxy-2-iodoglycosylacetates and O-iodobenzoates respectively from differently protected glycals have been developed. They are compatible with a variety of protecting groups and various functional groups at 2C-position. Hexose-3,2-enolone 8 is obtained directly from 2-acetoxy glycal 5 by method A. An application to modified method B has been shown by synthesis of a diastereomerically pure α-glycosyl ortho-hexynylbenzoate 12, a glycosyl donor from 3,4,6-tri-O-acetyl-D-glucal in two steps that has been further utilized in the synthesis of glycosides 13–18.
- Saidhareddy, Puli,Ajay, Sama,Shaw, Arun K.
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p. 4407 - 4417
(2017/07/03)
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- Sulfonium Salts of Iodine(I) Species as Efficient Reagents for the Regioselective Bisfunctionalisation of Glycals and Enol Ethers
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A new sulfonium-salt-based iodine(I) reagent system for the vicinal functionalisation of glycals and enol ethers has been developed. The unprecedented iodine(I) complex, Me3SI(OAc)2, generated in situ from Me3SI and PhI(OAc)2, effectively promoted the one-pot iodocarboxylation using carboxylic acids, and iodoazidation using NaN3 or TMSN3 (trimethylsilyl azide). The scope and generality of the new reagent was probed for a wide range of substrates, including various substituted aromatic carboxylic acids, heterocyclic, alicyclic, and aliphatic carboxylic acids, and amino acids to obtain various functionalised glycoconjugates in high yields (99 %) and with diastereoselectivities up to 100 %. A new sulfonium-salt-based iodine(I) reagent system has been developed for the vicinal functionalisation of glycals and enol ethers. The unprecedented iodine(I) complex generated in situ from Me3SI and PhI(OAc)2 effectively promoted iodocarboxylation and iodoazidation reactions in excellent yields and with diastereoselectivities up to 100 %.
- Reddy, Thurpu Raghavender,Rao, Dodla Sivanageswara,Babachary, Kalvacherla,Kashyap, Sudhir
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p. 291 - 301
(2016/02/18)
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- NaIO4-KI-NaN3 as a new reagent system for C-H functionalization in hydrocarbons
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The NaIO4-KI-NaN3 combination has been found to be an efficient, reliable, and inexpensive reagent system for mono- and 1,2-difunctionalization of hydrocarbons via C-H bond activation to afford vicinal azido- and acetoxy iodinations of cyclic hydrocarbons.
- Chouthaiwale, Pandurang V.,Suryavanshi, Gurunath,Sudalai, Arumugam
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scheme or table
p. 6401 - 6403
(2009/04/06)
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- Triiodoisocyanuric acid: a new and convenient reagent for regioselective coiodination of alkenes and enolethers with oxygenated nucleophiles
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The reaction of triiodoisocyanuric acid (prepared from I2 and trichloroisocyanuric acid in 90% yield) with alkenes in the presence of oxygenated nucleophilic solvents (alcohols, AcOH and H2O) led to the corresponding β-iodoethers, β-iodoacetates and iodohydrins, in 66-98% isolated yield. Enolethers reacted with triiodoisocyanuric acid in MeOH to produce dialkylacetals (70-83%).
- Ribeiro, Rodrigo da S.,Esteves, Pierre M.,de Mattos, Marcio C.S.
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p. 8747 - 8751
(2008/03/18)
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- A new synthesis of cis-diol from alkene using iodine-ammonium cerium(IV) nitrate
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The reaction mixtures of 5α-cholest-2-ene with iodine-ammonium cerium(IV) nitrate [CAN(IV)] were converted with potassium hydroxide in methanol-water to give the more hindered 2β,3β-diol in high yield. Cyclohexene and cycloheptene similarly reacted to the corresponding cis-diols in good yield. It was found that this reaction intermediate proceeds to give trans-iodoacetate via trans-iodonitrate. This new synthetic method provided several advantages over the Prevost reaction. Georg Thieme Verlag Stuttgart.
- Horiuchi, C. Akira,Dan, Gong,Sakamoto, Masaki,Suda, Kazuhiko,Usui, Shigeru,Sakamoto, Okihiko,Kitoh, Shinya,Watanabe, Satoshi,Utsukihara, Takamitsu,Nozaki, Sukekatsu
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p. 2861 - 2864
(2007/10/03)
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- Aerobic oxidation of alkenes to esters of vicinal diols with a syn-configuration catalyzed by I2 and the H5PV 2Mo10O40 polyoxometalate
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A new method for the synthesis of vicinal diols from alkenes has been developed. Reaction of molecular iodine in the presence of a polyoxometalate as oxidation catalyst under aerobic conditions in acetic acid solvent leads to the oxidative iodoacetoxylation of an alkene, i.e. formation of a 1,2-iodoacetate. Further in situ substitution of the iodide by water yields the 1,2-diol monoacetate with a predominantly (ca. 4.5:1) cis-configuration. Further esterification under the reaction's acidic conditions leads also to the cis-diacetate. The method may be valuable for the synthesis of cis-vicinal diols without use of toxic osmium catalysts. Georg Thieme Verlag Stuttgart.
- Branytska, Olena,Neumann, Ronny
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p. 2525 - 2527
(2007/10/03)
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- Regioselective synthesis of α-iodoacetates from alkenes/ammonium acetate/I2 by Woodward's reaction
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Regioselective synthesis of α-iodoacetates from alkenes, ammonium acetate, and iodine in acetic acid is reported. The reaction is facile, fast, environmentally, friendly, and cost effective. α-Iodoacetates are obtained from both acyclic and cyclic alkenes
- Myint, Yi Yi,Pasha
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p. 4477 - 4482
(2007/10/03)
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- Synthesis of α-iodoacetates from alkenes by cadmium acetate catalysed Woodward's reaction
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Alkenes on treatment with iodine and cadmium acetate in acetic acid give α-iodoacetates in high yields. The reaction is facile and α-iodoacetates are obtained from both acyclic and cyclic alkenes within 5-30 min.
- Myint, Yi Yi,Pasha
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p. 333 - 335
(2007/10/03)
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- Selective functionalisation of hydrocarbons by nitric acid and aerobic oxidation catalysed by N-hydroxyphthalimide and iodine under mild conditions
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Alkylbenzenes are selectively functionalised to the corresponding acetates by nitric aerobic oxidation catalysed by N-hydroxyphthalimide and iodine. With cyclohexane the oxidation leads to a mixture of cyclohexyl acetate and trans-2-iodocyclohexyl acetate. The mechanism is discussed.
- Minisci, Francesco,Recupero, Francesco,Gambarotti, Cristian,Punta, Carlo,Paganelli, Roberto
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p. 6919 - 6922
(2007/10/03)
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- Activation of alkanes upon reaction with PhI(OAc)2-I2
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You can also choose from alkanes! Either mono- or bifunctional iodo derivatives can be prepared from alkanes (see scheme) in an efficient and selective manner by using PhI(OAc)2, I2, and an alcohol.
- Barluenga, Jose,Gonzalez-Bobes, Francisco,Gonzalez, Jose M.
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p. 2556 - 2558
(2007/10/03)
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- Phosphonium salts of diacetoxyiodine(I) anions, new reagents for the iodoacetoxylation of alkenes
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Novel phosphonium salts of diacetoxyiodine(I) anions 1 add to alkenes like tri-O-benzyl galactal 8 affording 1-acetoxy-2-iodopyranoses 12a,b which can efficiently be employed in the synthesis of 2-deoxyglycoside 14.
- Kirschning, Andreas,Plumeier, Claus,Rose, Lars
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- Oxidation of alkyl and aryl iodides, phenylacetaldehyde and alkenes by dimethyldioxirane. Reaction products and mechanism
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Alkyl and aryl iodides are smoothly oxidized to iodosoderivatives and phenylacetaldehyde is oxidized to phenylacetic acid or benzyl acetate by dimethyldioxirane depending on the presence or not of oxygen. These results and the epoxidation or the allylic oxidation of alkenes by the same reagent are explained by a general free-radical mechanism.
- Bravo, Anna,Fontana, Francesca,Fronza, Giovanni,Minisci, Francesco,Serri, Anna
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p. 6945 - 6948
(2007/10/02)
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- New, simple 1,2-iodoacetoxylation of alkenes+
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A general synthetic procedure for the preparation of trans-1,2- iodoacetates in good yields from alkenes by reaction with lead diacetate and iodine is reported.
- Bedekar,Nair,Soman
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p. 2299 - 2305
(2007/10/02)
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- β-Functionalised radicals in organic synthesis: 2-Acyloxyalkyl radicals from 2-acyloxyalkyl iodides by the tin route
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The reaction of iodoesters 1a-c with electrophilic olefins 2a-d and in situ generated tributyltin hydride (from a substoichiometric amount of tributyltin chloride and an excess of sodium borohydride) in the presence of a catalytic amound of AIBN in ethanol at 0 to 20°C yields the expected coupling products 3aa-3cd. Products 4 resulting from an iodine/hydrogen exchange are also obtained as by-products in variable amounts. The stereochemistry of the coupling reaction is studied: starting from trans-2-iodocyclohexyl acetate (1d) and methyl acrylate (2a) a 1/3 mixture of the corresponding cis/trans diastereoisomers is obtained. This result indicates that the corresponding radical coupling is not stereospecific.
- Foubelo, Francisco,Lloret, Francisco,Yus, Miguel
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p. 5131 - 5138
(2007/10/02)
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- The Use of Bismuth(III) Acetate in 'Wet' and 'Dry' Prevost Reactions
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cis-Diol and trans-diol derivatives can be prepared from alkenes by reaction with iodine and bismuth(III) acetate in 'wet' and 'dry' acetic acid, respectively.Reactions using lesser amounts of bismuth(III) acetate under 'dry' conditions give iodo acetates and under 'wet' conditions a mixture of iodohydrins and iodo ethers.Comparison of these reactions with those promoted by silver, copper, mercury and thallium salts is included.
- Trainor, Robert W.,Deacon, Glen B.,Jackson, W. Roy,Giunta, Nunzio
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p. 1265 - 1280
(2007/10/02)
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- A New Alkoxyiodination and Nitratoiodination of Olefins Using Iodine-Cerium(IV) Ammonium Nitrate
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Reactions of cycloolefins with iodine-cerium(IV) ammonium nitrate in alcohols (methanol, ethanol, 1-propanol, and 2-propanol) under reflux gave the corresponding vicinal alkoxyiodocycloalkanes in good yields.In the case of t-butyl alcohol, trans-iodo nitr
- Horiuchi, C. Akira,Nishio, Yoshihiko,Gong, Dan,Fujisaki, Takanori,Kiji, Shinji
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p. 607 - 610
(2007/10/02)
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- Bismuth(III) Acetate: A Cheap, Efficient, and Environmentally Acceptable Reagent for 'Wet' and 'Dry' Prevost Reactions
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cis- and trans-Diol derivatives can be prepared from alkenes by reaction with bismuth(III) acetate in 'wet' and 'dry' acetic acid respectively.
- Campi, Eva M.,Deacon, Glen B.,Edwards, Gavin L.,Fitzroy, Mark D.,Giunta, Nunzio,et al.
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p. 407 - 408
(2007/10/02)
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- Supported Reagents in Facile and Selective Two-phase Additions to C=C Double Bonds
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Inorganic-solid-supported KSCN, NaN3, and KOAc mixed with iodine and an alkene in CHCl3 gave products by a facile two-phase addition.
- Ando, Takashi,Clark, James H.,Cork, David G.,Fujita, Mitsue,Kimura, Takahide
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p. 1301 - 1302
(2007/10/02)
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- Reactions of Iodine(I) Acetate with Alkenes and Vicinal Diols
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The chemoselectivities of the reactions of iodine(I) acetate and iodine(I) acetate-thallium(I) acetate with cis-cyclooct-5-ene-1,2-diol have been investigated.The addition of iodine(I) acetate to cyclo-octa-1,5-diene, for a number of reagent systems, results in products arising from both 1,2-addition and transannular pathways.
- Cambie, Richard C.,Rutledge, Peter S.,Stewart, Georgina M.,Woodgate, Paul D.,Woodgate, Sheila D.
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p. 1689 - 1698
(2007/10/02)
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- LEAD(IV)ACETATE-METAL HALIDE REAGENTS II. A NEW METHOD FOR THE SYNTHESIS OF β-HALO CARBOXYLATES AND β-IODO ETHERS
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A new method for the synthesis of trans-β-halo carboxylates and trans-β-iodo ethers from alkenes using lead(IV)acetate-metal halide is described.KEYWORDS - lead(IV)acetate; metal halide; alkene; trans-β-halo carboxylate; trans-β-iodo ether
- Motohashi, Shigeyasu,Satomi, Masakichi,Fujimoto, Yasuo,Tatsuno, Takashi
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p. 1788 - 1791
(2007/10/02)
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- THE DEGRADATION OF CARBOXYLIC ACIDS INTO ALDEHYDES. REGIOSELECTIVE α-ACETOXYLATION OF 1,2,4-TRIAZOLIUM SALTS WITH DIACETOXYIODATE(1)ANION
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A novel method was developed for degradation of carboxylic acid into aldehydes containing one C atom less whose key step consists in α-acetoxylation of 5-alkyl-3-methylthio-1,4-diphenyl-1,2,4-triazolium iodides by (diacetoxyiodo)benzene.The mechanism of the regioselective α-acetoxylation was studied and the diacetoxy-iodate(1)anion was shown to be the actual oxidising agent.Further oxidation reactions of tetraethylammonium diacetoxyiodate(1) were investigated.A novel method was developed for the oxidation of primary alkyl amines into aldehydes by the novel heterocyclic reagent 5-bromo-3-methylthio-1,4-diphenyl-1,2,4-triazolium bromide and diethyl azodicarboxylate.
- Doleschall, Gabor,Toth, Gabor
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p. 1649 - 1666
(2007/10/02)
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