- Exhaustive One-Step Bridgehead Methylation of Adamantane Derivatives with Tetramethylsilane
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A methylation protocol of adamantane derivatives was investigated and optimized using AlCl3 and tetramethylsilane as the methylation agent. Substrates underwent exhaustive methylation of all available bridgehead positions with yields ranging from 62 to 86 %, and up to six methyl groups introduced in one step. Scaling-up of the reaction was demonstrated by performing the >40 gram-scale synthesis of 1,3,5,7-tetramethyladamantane with 62 % yield. For several substrates, rearrangements were observed, as well as cleavage of functional groups or Csp3?Csp2 bonds or even cyclohexyl-adamantyl bonds. Based on mechanistic studies, it is suggested that a reactive methylation complex is formed from tetramethylsilane and AlCl3. X-ray diffraction structures of hexamethylated bis-adamantyls reveal elongation or widening of sp3 carbon bonds between adamantyl moieties to 1.585(3) ? and 125.26(9)° due to repulsive H???H contacts.
- Bonsir, Maxime,Davila, Christian,Geerts, Yves,Kennedy, Alan R.
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supporting information
p. 5227 - 5237
(2021/10/19)
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- Study of the liquid-vapor critical temperatures for methyladamantanes and their mixtures with cyclohexane
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The liquid-vapor critical temperatures of individual 1,3-dimethyl-and 1,3,5-trimethyladamantanes and their binary mixtures with cyclohexane were determined over the entire range of composition by means of the ampule method. It was found that an excess of the critical temperatures over calculated values reached 20 K for both mixtures studied. The predictive capabilities of several calculation methods are discussed. Nauka/Interperiodica 2006.
- Nazmutdinov,Sarkisova,Vodenkova,Nesterov,Nesterova
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p. 428 - 433
(2007/10/03)
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- Triflic acid-catalyzed adamantylation of aromatics in [BMIM][OTf] ionic liquid; synthetic scope and mechanistic insight
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A mild and efficient process has been developed for the one-pot adamantylation of aromatic substrates employing 1-AdaOH, 1-AdaCl, 1-AdaBr, and 1-Br-3,5,7-trimethyladamantane as adamantylating agents, with triflic acid (TfOH) as promoter and n-butylmethylimidazolium triflate [BMIM][OTf] room temperature ionic liquid (IL) as solvent. The influence of reaction temperature, reaction time and the amount of TfOH was gauged in model reactions employing 1-AdaOH, 1-AdaCl and 1-AdaBr with toluene as the substrate. Under optimal conditions, the reactions exhibit high para selectivity with little or no adamantane side-product being formed. The synthetic scope of this transformation was tested for representative alkylbenzenes and haloalkylbenzenes. Comparative reactions carried out in 1,2-dichloroethane (DCE) produce increased amounts of the meta isomer and substantial amounts of adamantane. Substrate selectivities (KT/KB) were measured in competitive experiments in [BMIM][OTf] and in DCE as solvents. Isomerization tests were performed to shed light on the origin of the meta isomer. A DFT study was also conducted to compare relative stabilities of the isomeric products, to gauge the relative stabilities of the intermediate isomeric benzenium ions of adamantylation and their charge distribution modes, and to explore the intramolecular process for isomerization in the benzenium ion. The Royal Society of Chemistry 2005.
- Laali, Kenneth K.,Sarca, Viorel D.,Okazaki, Takao,Brock, Aaron,Der, Paul
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p. 1034 - 1042
(2007/10/03)
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- The standard molar enthalpies of formation of some alkyladamantanes
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The standard massic energies of combustion of three alkyl-derivative of adamantane were measured at T = 298.15 K by static-bomb combustion calorimetry. The standard molar enthal pi es of formation in the liquid and gaseous states were obtained from these data. The enthalpies of some reactions of isomerization were calculated from the equilibrium study and compared with the results of calorimetric measurements.
- Melkhanova,Pimenova,Kolesov,Pimerzin,Sarkisova
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p. 1311 - 1317
(2007/10/03)
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- NOUVEAUX DECONTAMINANTS. DESTRUCTION DE TOXIQUES ORGANOPHOSPHORES OU SOUFRES PAR DES PERACIDES MONO-, BI- ET TRICYCLIQUES SATURES
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New peroxycarboxylic and peroxyacetic acids have been tested for the destruction of some organophosphorus compounds and mustards.The peroxyacids used have monocyclic, bicyclic or tricyclic structures.These are very reactive against paraoxon or HD and the addition of certain surfactants enhances the reaction rate.Very short half-live times are obtained with these compounds.
- Lion, C.,Hedayatullah, M.,Bauer, P.,Boukou-Poba, J. P.,Charvy, C.,et al.
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p. 249 - 256
(2007/10/02)
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- Contribution a l'etude des reactions d'alkylation et de polyalkylation de l'adamantane et de ses homologues
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A method for preparing alkyl derivatives of cage-structure compounds is proposed.It relies on the use of Grignard reactions with a high boiling point solvent.The reactions take place at atmospheric pressure.Methylation of adamantane, diamantane, and homoadamantane occurs with quantitative yield.With other primary alkyl groups, yields are better than 60percent.Competition between alkylation and secondary reactions is discussed on the basis of a free radical mechanism.
- Molle, G.,Dubois, J. E.,Bauer, P.
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p. 2428 - 2433
(2007/10/02)
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- ADAMANTANE AND ITS DERIVATIVES IN IONIC METHYLATION
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The ionic methylation of adamantane and 1-hydroxy-, 1-chloro-, and 1-bromoadamantanes was realized with tetramethylsilane in the presence of aluminum halides; the products were mono- and polyalkyladamantanes.Compounds of the adamantane series are methylated more readily than the analogous derivatives of cyclic and acyclic hydrocarbons of other types; the reaction takes place under mild conditions and leads to the production of methylation products with overall yields close to quantitative.
- Bolestova, G. I.,Parnes, Z. N.,Kursanov, D. N.
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p. 297 - 300
(2007/10/02)
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- ORGANOLITHIENS A STRUCTURE "CAGE". REACTIVITE VIS-AVIS DES CETONES NON ENOLISABLES. COEXISTENCE D"UN COMPLEXE EVOLUTIF ET D'UN COMPLEXE INERTE.
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The dark orange color produced by the condensation of an excess of lithium compound IV with ketone II was monitored by U.V. and stopped flow spectroscopy.This coloring was ascribed to a lithium compound-ketone complex which evolves into condensation alcohol V.In determining the reaction products we detect the existence of a second inert complex which, when hydrolized, releases the initial ketone.
- Lozach, D.,Molle, G.,Bauer, P.,Dubois, J. E.
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p. 4213 - 4216
(2007/10/02)
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- High-Yield Direct Synthesis of a New Class of Tertiary Organolithium Derivatives of Polycyclic Hydrocarbons
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For the first time, 1- and 2-adamantyllithium, 1-diamantyllithium, 3,5,7-trimethyl-1-adamantyllithium, 1-twistyllithium, 3-methyl-7-noradamantyllithium, 1-triptycyllithium, and 3-homoadamantyllithium have been directly synthesized from the reaction of an organic halide and lithium metal.By use of certain experimental parameters, the phenomena at the metal-solution interface are controlled, thereby resulting in exceptionally high yields of this new class of organometallic compounds (>75percent, except in the case of 3-homoadamantyllithium).Competition between formation of the organometallic compound and formation of solvent-attack byproducts is determined by the degree of adsorption of the transient species (anion radical RX-. or radical pair R..Li) generated at the metal surface during attack by the halogenated derivative.
- Molle, G.,Bauer, P.,Dubois, J. E.
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p. 2975 - 2981
(2007/10/02)
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- Fused and Bridged Tetracyclic C13 and C14 Adamantanes. Synthesis of Methyl-2,4-ethano-, 1,2-Trimethylene-, 2,4-Trimethylene-, and 1,2-Tetramethyleneadamantane
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Carbocation isomerization of methyltetracyclododecanes 1 and 2 gives an equilibrium mixture (5:3:2) of 1-, 2-, and 8-methylethanoadamantanes 15-17.By contrast, a tetracyclotridecane (3) which does not contain a methyl group rearranges under mild conditions to a mixture (97:3) of 1,2- and 2,4-trimethyleneadamantane (18 and 19).Under more vigorous conditions, the two sets of products interconvert, but determination of an equilibrium composition is hampered by extensive fragmentation with the formation of alkyladamantanes.Isomerization of a tetracyclotetradecane precursor (34) leads to 1,2-tetramethyleneadamantane (36) as the sole product.The products of rearrangement (15-19 and 36) are consistent with the results of empirical force field calculations.It is suggested that such calculations might be relied upon to predict the most stable isomers when kinetic barriers or extensive side reactions prevent an accurate experimental determination of the equilibrium composition.Possible rearrangement mechanisms for the conversions 3 -> 18/19 and 34 -> 36 were analyzed by means of the isomerization graph composed of all isomers connected by 1,2 alkyl shifts.Plausible pathways involving eleven steps for isomerization of 3 into 18 and eight steps for the isomerization of 34 into 36 are identified.
- Osawa, Eiji,Tahara, Y.,Togashi, A.,Iizuka, Takeshi,Tanaka, Nobuhide,Kan, Tadayoshi
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p. 1923 - 1932
(2007/10/02)
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