- EINE EINFACHE METHODE ZUR DARSTELLUNG TERTIAERER IODIDE
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Hindered alkyl iodides may be prepared conveniently by treatment of the corresponding alcohols with magnesium iodide in n-pentane.
- Martinez, A. Garcia,Alvarez, R. Martinez,Vilar, E. Teso,Fraile, A. Garcia,Barcina, J. Osio,et al
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- Photoinduced Palladium-Catalyzed Dicarbofunctionalization of Terminal Alkynes
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Herein, a conceptually distinct approach was developed that allowed for the dicarbofunctionalization of alkynes at room temperature using simple, bench-stable alkyl iodides and a second molecule of alkyne as coupling partner. Specifically, the photochemical activation of palladium complexes enabled this strategic dicarbofunctionalization via addition of alkyl radicals from secondary and tertiary alkyl iodides and formation of an intermediate palladium vinyl complex that could undergo subsequent Sonogashira reaction with a second alkyne molecule. This alkylation–alkynylation sequence allowed the one-step synthesis of 1,3-enynes including heteroarenes and biologically active compounds with high efficiency without exogenous photosensitizers or oxidants and now opens up pathways towards cascade reactions via photochemical palladium catalysis.
- Yang, Zhen,Koenigs, Rene M.
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supporting information
p. 3694 - 3699
(2021/02/01)
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- Visible-light-mediated multicomponent reaction for secondary amine synthesis
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The widespread presence of secondary amines in agrochemicals, pharmaceuticals, natural products, and small-molecule biological probes has inspired efforts to streamline the synthesis of molecules with this functional group. Herein, we report an operationally simple, mild protocol for the synthesis of secondary amines by three-component alkylation reactions of imines (generated in situ by condensation of benzaldehydes and anilines) with unactivated alkyl iodides catalyzed by inexpensive and readily available Mn2(CO)10. This protocol, which is compatible with a wide array of sensitive functional groups and does not require a large excess of the alkylating reagent, is a versatile, flexible tool for the synthesis of secondary amines.
- Wang, Xiaochen,Zhu, Binbing,Dong, Jianyang,Tian, Hao,Liu, Yuxiu,Song, Hongjian,Wang, Qingmin
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supporting information
p. 5028 - 5031
(2021/05/28)
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- Visible-Light-Mediated C-I Difluoroallylation with an α-Aminoalkyl Radical as a Mediator
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Herein, we report a protocol for direct visible-light-mediated C-I difluoroallylation reactions of α-trifluoromethyl arylalkenes with alkyl iodides at room temperature with an α-aminoalkyl radical as a mediator. The protocol permits efficient functionalization of various α-trifluoromethyl arylalkenes with cyclic and acyclic primary, secondary, and tertiary alkyl iodides and is scalable to the gram level. This mild protocol uses an inexpensive mediator and is suitable for late-stage functionalization of complex natural products and drugs.
- Yue, Fuyang,Dong, Jianyang,Liu, Yuxiu,Wang, Qingmin
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supporting information
p. 7306 - 7310
(2021/10/01)
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- A mild and highly chemoselective iodination of alcohol using polymer supported DMAP
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The synthesis of organic compounds using polymer supported catalysts and reagents, where the required product is always in solution, has been of great interest in recent years, both in industries and academia especially in pharmaceutical research. Here, a simple and efficient method for conversion of alcohols into their iodides in high yield using polymer supported 4-(Dimethylamino)pyridine (DMAP) is described. Polymer supported DMAP is used in catalytic amount and is recovered and reused several times. Additionally, this method is highly chemoselective. [Figure not available: see fulltext.]
- Das, Diparjun,H Anal, Jasha Momo,Rokhum, Lalthazuala
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p. 1695 - 1701
(2017/03/08)
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- An efficient and selective method for the iodination and bromination of alcohols under mild conditions
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A straightforward and effective procedure for the conversion of a variety of alcohols into the corresponding alkyl iodides and bromides is described using KX/P2O5 (X = I, Br). The reactions were easily carried out in acetonitrile under mild conditions. Using this method, the selective conversion of benzylic alcohols in the presence of aliphatic alcohols was achieved.
- Khazdooz, Leila,Zarei, Amin,Aghaei, Hamidreza,Azizi, Ghobad,Gheisari, Mohammad Mehdi
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p. 168 - 171
(2015/12/30)
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- A mild method for the replacement of a hydroxyl group by halogen. 1. Scope and chemoselectivity
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α-Chloro-, bromo- and iodoenamines, which are readily prepared from the corresponding isobutyramides have been found to be excellent reagents for the transformation of a wide variety of alcohols or carboxylic acids into the corresponding halides. Yields are high and conditions are very mild thus allowing for the presence of sensitive functional groups. The reagents can be easily tuned allowing therefore the selective monohalogenation of polyhydroxylated molecules. The scope and chemoselectivity of the reactions have been studied and reaction mechanisms have been proposed.
- Munyemana, Fran?ois,George, Isabelle,Devos, Alain,Colens, Alain,Badarau, Eduard,Frisque-Hesbain, Anne-Marie,Loudet, Aurore,Differding, Edmond,Damien, Jean-Marie,Rémion, Jeanine,Van Uytbergen, Jacqueline,Ghosez, Léon
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p. 420 - 430
(2015/12/31)
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- Iodination of alcohols over Keggin-type heteropoly compounds: A simple, selective and expedient method for the synthesis of alkyl iodides
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Different catalysts derived from Keggin-type heteropoly compounds were prepared and their catalytic activities have been compared in the iodination of benzyl alcohol with KI under mild reaction conditions. A high catalytic activity was found over tungstophosphoric acid supported on silica and titania. The effect of catalyst loading, iodine source and the nature of substituents on the aromatic ring of benzyl alcohol were investigated. Finally, several competitive reactions were studied between structurally diverse alcohols. This protocol provides a mild and expedient way for the conversion of various alcohols to their corresponding alkyl iodides with high selectivity.
- Rafiee, Ezzat,Mahdavia, Houri,Joshaghani, Mohammad
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experimental part
p. 135 - 140
(2011/06/09)
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- Iodine-hexamethyldisilane (HMDS)-mediated anomerization of peracetylated 1,2-trans-linked alkyl and aryl glycosides
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Treatment of peracetylated alkyl and aryl 1,2-trans-glycosides with iodine in the presence of HMDS has been found to result in the anomerization leading to the formation of the respective 1,2-cis-glycosides. In the case of alkyl glycosides with aglycons of short alkyl chain length complete anomerization to the α-glycosides was observed while with those of longer chain length the process was found to be incomplete. The observations have been interpreted mechanistically.
- Malik, Satish,Shah, Krupesh J.,Ravindranathan Kartha
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scheme or table
p. 867 - 871
(2010/06/14)
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- Silicaphosphine (Silphos): A filterable reagent for the conversion of alcohols and thiols to alkyl bromides and iodides
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Silicaphosphine (Silphos), [P(Cl)3-n(SiO2) n], as a new heterogeneous reagent is introduced. This reagent converts alcohols and thiols to their corresponding bromides and iodides in the presence of X2 (X=Br, I) in refluxing CH3CN in high to quantitative yields. Use of Silphos provides a highly practical method for the easy separation of the Silphos oxide byproduct by a simple filtration.
- Iranpoor, Nasser,Firouzabadi, Habib,Jamalian, Arezu,Kazemi, Foad
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p. 5699 - 5704
(2007/10/03)
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- Photolysis of 1-alkylcycloalkanols in the presence of (diacetoxyiodo) benzene and I2. Intramolecular selectivity in the β-scission reactions of the intermediate 1-alkylcycloalkoxyl radicals
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The C-C β-scission reactions of 1-alkylcycloalkoxyl radicals, generated photochemically by visible light irradiation of CH2Cl 2 solutions containing the parent 1-alkylcycloalkanols, (diacetoxy)-iodobenzene (DIB), and I2, have been investigated through the analysis of the reaction products. The 1-alkylcycloalkoxyl radicals undergo competition between ring opening and C-alkyl bond cleavage as a function of ring size and of the nature of the alkyl substituent. With the 1-propylcycloheptoxyl, 1-propylcyclooctoxyl, and 1-phenylcyclooctoxyl radicals, formation of products deriving from an intramolecular 1,5-hydrogen atom abstraction reaction from the cycloalkane ring has also been observed. The results are discussed in terms of release of ring strain associated to ring opening, stability of the alkyl radical formed by C-alkyl cleavage, and with cycloheptoxyl and cyclooctoxyl radicals, also in terms of the possibility of achieving a favorable geometry for intramolecular hydrogen atom abstraction.
- Antunes, Carla S. Aureliano,Bietti, Massimo,Lanzalunga, Osvaldo,Salamone, Michela
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p. 5281 - 5289
(2007/10/03)
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- Acyl iodides in organic synthesis: I. Reactions with alcohols
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Reaction of acyl iodides RC(O)I (R = Me, Ph) with alcohols R′OH (R′ = Me, Et, i-Pr, t-Bu, CH2= CHCH2, HC≡CCH2) provides in the corresponding organyl iodides R′I. Unlike that 2-chloroethanol and phenol (R′ = CH 2CH2Cl, Ph) react with RC(O)I in the same way as with acyl chlorides yielding esters RCO2R′. This reaction path occurs partially also with methanol and ethanol.
- Voronkov,Trukhina,Vlasova
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p. 1576 - 1578
(2007/10/03)
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- Mild conversion of alcohols to alkyl halides using halide-based ionic liquids at room temperature
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Formula presented Alcohols were efficiently converted to alkyl halides using 1-n-butyl-3-methylylimidazolium halides (ionic liquids) in the presence of Bronsted acids at room temperature. The alkyl halide products were easily isolated from the reaction mixture via simple decantation or extraction, and the 1-n-butyl-3-methylimidazolium cation could be recycled for further uses.
- Ren, Rex X.,Wu, Jeff Xin
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p. 3727 - 3728
(2007/10/03)
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- The versatile behavior of the PdCl2/Et3SiH system. Conversion of alcohols to the corresponding halides and alkanes
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The versatility of the palladium(II) chloride/triethylsilane system has been tested in the transformation of alcohols. The conversion to the corresponding halides and alkanes has been achieved in good yields and in the absence of solvent for a variety of substrates.
- Ferreri,Costantino,Chatgilialoglu,Boukherroub,Manuel
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p. 135 - 137
(2007/10/03)
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- The Stoichiometry in the Determination of Water Using Karl Fischer Reagent
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The stoichiometry of the Karl Fischer reaction is not unambiguous. The titer of a Karl Fischer solution rises with the amount of water, because sulphur trioxide which is formed as an intermediate consumes water too. An 1:1-stoichiometry (H2O:I2) can be simulated by alcohols, because these solvents also react with iodine and sulphur dioxide leading to additional consumption of iodine during the titration. This interpretation of the results of Karl Fischer titrations is supported by the isolation or identification of pertinent reaction products.
- Fischer, Wolfgang,Krenn, Karl-Dieter
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p. 569 - 577
(2007/10/03)
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- Direct Conversion of Alcohols into the Corresponding Iodides
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A mild and effective procedure for directly converting secondary, tertiary and benzylic alcohols into the corresponding iodides is described using I2 in refluxing petroleum ether.The reaction proceeds with inversion of configuration.
- Joseph, Reni,Pallan, S. Pradeep,Sudalai, A.,Ravindranathan, T.
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p. 609 - 612
(2007/10/02)
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- Novel reactions of perfluoroalkylphenyl sulfides with organolithium reagents
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The reaction of anisole with organolithium reagents, commonly known as ortho-directed metallation, is of considerable synthetic utility in organic chemistry and as such has attracted considerable attention in recent years.Over the past 50 years, several mechanisms have been proposed to account for the observed regioselective metallation.For the first time, the reaction of perfluoroalkylphenyl sulfides with organolithium reagents has been investigated and found to furnish products resulting from the replacement of the perfluoroalkyl moieties with alkyl groups derived from the metallating agents.Phenyltrifluoromethyl ether, the anisole analog, failed to undergo metallation.A rationalization for the formation of unusual products via mediation of a single-electron-transfer process is presented in this paper together with the spectral data of the products. - Keywords: Reactions; Perfluoroalkylphenyl sulfides; Organolithium reagents; NMR spectroscopy; Mass spectrometry; Orthometallation
- Munavalli, S.,Hassner, A.,Rossman, D. I.,Singh, S.,Rohrbaugh, D. K.,Ferguson, C. P.
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- PHOTOLYSE DE HI DANS UNE MATRICE HYDROCARBONEE VITREUSE A 77 K
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Stable products from the photolysis of HI in methyl-3 pentane (3 MP) or dimethyl-2,3 butane (23 DMB) quenched solid at 77 K are analyzed by capillary gas chromatography.Selective formation of a tertiary radical is proposed for the 23 DMB/HI system ; in 3 MP/HI, C-H bond rupture is also localized at the weakest tertiary bond, however the scission is not selective.
- Laet, M. de,Tilquin, B.
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- RAPID SYNTHESIS OF α,β UNSATURATED IODIDES: IODINATION UNDER VACUUM WITH SOLID DIPHOSPHORUS TETRAIODIDE
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α,β unsaturated alcohols are transformed in 2-5 mn and in 70-90percent yield (> 90percent pure) into their corresponding iodides when they are allowed to react with solid P2I4 under 10-2 Torr at 85 deg C.With unsymmetrical alcohols, an allylic rearrangement always leads to the more stable iodide.
- Lasne, Marie- Claire,Cairon, Philippe,Villemin, D.
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- New General Processes of Homolytic Alkylation of Heteroaromatic Bases by t-BuOOH or (t-BuO)2 and Alkyl Iodides
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New general, selective processes of homolytic alkylation of protonated heteroaromatic bases have been developed using alkyl iodides and t-BuOOH or (t-BuO)2 as sources of alkyl radicals.Both processes are based on the generation of methyl radical from the peroxides, and on iodine abstraction from the alkyl iodide by the methyl radical.The selective processes are the result of combined enthalpic and polar effects.The enthalpic factor governs the equilibrium of iodine abstraction, whereas the polar effect governs the reactivity of the alkyl radicals with the protonated heteroaromatic ring.A redox chain is operative with t-BuOOH and an unusual free-radical chain process is involved with (t-BuO)2.Both chains are particularly effective because of the electron-transfer oxidation of the pyridyl radical intermediate, the ionization potential of which (5.4-6.0 eV) is close to that of lithium (5.39 eV) or sodium (5.14 eV).
- Fontana, Francesca,Minisci, Francesco,Barbosa, Maria Claudia Nogueira,Vismara, Elena
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p. 995 - 999
(2007/10/02)
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- Allylic and Propargylic Substitution Reactions Involving Radicals Generated from Alkylmercury Halides
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Addition of alkyl radicals to allyl or propargyl derivatives forms adduct radicals which can undergo β-elimination with substituents such as halogen, PhS, PhSO2, Bu3Sn, or HgCl to form the alkyl-substituted propene or allene and an eliminated radical which regenerates the alkyl radical by displacement from an alkylmercurial.With β-oxy substituents, such as O2CR, OP(O)(OEt)2, O3SAr, OPh, OSiMe3, or OH, the adduct radicals can displace the alkyl radical from the alkylmercurial to yield β-substituted alkylmercurials which spontaneously, or in the presence of nucleophiles, undergo an elimination reaction to yield the alkene or allene.Relative reactivities toward tert-butyl radical attack, such as k(allyl chloride)/k(propargyl chloride) = ca. 10, have been determined.A similar relative reactivity is observed in reaction with (t-Bu)2CuLi implicating attack by free tert-butyl radicals.With allyl or propargyl iodide, radical attack leads to iodine atom abstraction.Reaction of propargyl iodide with t-BuHgCl/hν, (t-Bu)2CuLi, or (t-Bu)3ZnLi leads to a mixture of hydrocarbons in which tert-butylallene is present in only trace amounts.Benzene is an important reaction product which seems to be formed via the cyclodimerization of two "propargyl" (C3H3.) radicals.
- Russell, Glen A.,Ngoviwatchai, Preecha,Wu, Yuh Wern
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p. 4921 - 4927
(2007/10/02)
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- Photolysis of N-Alkoxybenzoquinone Imine N-Oxides
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Photolyses of a series of N-alkoxybenzoquinone imine N.oxides give products arising mainly from alkyl radicals, the solvent, and the several quinonoid species present in the reaction mixture.The alkyl radicals may be derived by fragmentation of the corresponding alkoxynitrenes which also rearrange to nitroso-compounds and hence to oximes.
- Baldry, Peter J.,Forrester, Alexander R.,Ogilvy, Munro M.,Thomson, Ronald H.
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p. 2035 - 2040
(2007/10/02)
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- Heats of Formation of Some Simple Alkyl Radicals
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Equilibrium constants, K, for the system Me + RI MeI + R were measured in solution by using electron paramagnetic resonance spectroscopy.Given the entropies of the components of the equilibrium and the heats of formation of the iodides, the relative heats of formation of the alkyl radicals were obtained.With δHf,300(Me) = 34.4 kcal mol-1 chosen as a standard, the following heats of formation for other alkyl radicals were obtained: Et, 28.0; n-Pr, 22.8; i-Pr, 19.2; s-Bu, 13.9; c-C5H9, 25.1; t-Bu, 9.4 kcal mol-1.These data lead to the following C-H bond dissotiation energies for simple alkanes: primary C-H, ca. 100; secondary C-H, ca. 96; tertiary C-H, ca. 94 kcal mol-1.
- Castelhano, A. L.,Griller, D.
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p. 3655 - 3659
(2007/10/02)
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- Carbon-Halogen Bonding Studies. Halogen Redistribution Reactions between Alkyl or Acetyl Halides and Tri-n-butyltin Halides
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The equilibrium positions have been determined for the halogen redistribution reactions of tri-n-butyltin halides with a variety of structurally different types of alkyl halides and with acetyl halides.These have been related through the reaction ΔGo values to carbon-halogen bond dissociation energy differences.It is suggested that the trends observed in the latter may provide evidence for the existence of a small steric bond weakening effect in the order C-I > C-Br > C-Cl bonds on going from methyl to primary, secondary, and tertiary alkyl halides.On the other hand, with the 2,3-? bond containing allyl, benzyl, and propargyl halides , α-haloacetones, and haloacetonitriles, there may be some type of electronic carbon-halogen bond strengthening effect which lies in order C-I > C-Br > C-Cl.Finally, for the acetyl halides, the data are in agreement with increases in bond strengths resulting from ? contributions being in the order C-Cl > C-Br > C-I.
- Friedrich, Edwin C.,Abma, Charles B.
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p. 1367 - 1371
(2007/10/02)
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- A Convenient Method for the Preparation of Highly Pure t-Alkyl Bromides and Iodides
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Highly pure (99-100 percent) t-butyl and t-pentyl bromides and iodides, and 3-bromo-3-ethylpentane were readily prepared in 83-95 percent yields by the reactions of the corresponding alcohols with hydrobromic or hydroiodic acid, using lithium or calcium halide.The metal halides remarkably increased the yield and the purity of the products.
- Masada, Hiromitsu,Murotani, Yoshiharu
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p. 1181 - 1182
(2007/10/02)
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