- 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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- Direct observation of cyclic carbenium ions and their role in the catalytic cycle of the methanol-to-olefin reaction over chabazite zeolites
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Carbenium ions in zeolites: Two important carbenium ions have been observed for the first time under working conditions of the methanol-to-olefins (MTO) reaction over chabazite zeolites using 13C NMR spectroscopy. Their crucial roles in the MTO
- Xu, Shutao,Zheng, Anmin,Wei, Yingxu,Chen, Jingrun,Li, Jinzhe,Chu, Yueying,Zhang, Mozhi,Wang, Quanyi,Zhou, You,Wang, Jinbang,Deng, Feng,Liu, Zhongmin
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supporting information
p. 11564 - 11568
(2013/11/06)
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- Alkylation of adamantane with alkyl halides catalyzed by ruthenium complexes
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The feasibility of catalytic alkylation of adamantane and 1-bromoadamantane with alkyl halides in the presence of ruthenium-containing catalysts was revealed. The optimum molar ratios between the catalyst components and the reactants, as well as the reaction conditions for the selective synthesis of mono-and dialkylsubstituted adamantane derivatives with a 70-98% yield, were determined. Nauka/Interperiodica 2006.
- Khusnutdinov,Schchadneva,Malikov,Dzhemilev
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p. 159 - 163
(2007/10/03)
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- The mechanism of conversion of saturated hydrocarbons catalyzed by sulfated metal oxides: Reaction of adamantane on sulfated zirconia
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The high activity of sulfated zirconia (SZ) toward hydrocarbon conversions has been confirmed by the study of the isomerization of methylcyclopentane to cyclohexane. This catalytic activity is generally rationalized by the catalyst having superacidic strength. The reaction of methylcyclopentane with superacids is initiated, however, by the cleavage of a carbon-carbon bond with the formation of an acyclic carbocation, followed by hydride transfer giving the methylcyclopentyl cation which undergoes rearrangement. By contrast, no isohexanes (products of ring cleavage) were formed in the reaction on SZ, suggesting a different reaction mechanism. The mechanism of interaction of SZ with saturated hydrocarbons was elucidated by a study of adamantane. Small amounts of 1-adamantanol and adamantanone and traces of 2-adamantanol were observed after reaction at temperatures from 65 to 135°C, indicating that the reaction is an oxidation followed by hydride transfers. Small amounts of diadamantanes were also formed, proving that oxidation to carbocations goes through the free radical stage. At 150°C, additional reaction products were observed, 1-adamantanethiol (larger amount) and 2-adamantanethiol (smaller amount), indicating reduction of sulfate all the way to sulfide, which then traps the adamantyl cation in competition with the oxygen anions or water formed in the redox process. Ring cleavage and disproportionation to form alkyladamantanes and aromatics also occurred. Thus, the increase in activity of SZ over the parent oxide for carbocationic alkane and cycloalkane reactions can be ascribed to initiation through a one-electron oxidation of the hydrocarbon by sulfate to a carbocation precursor.
- Farcasiu, Dan,Ghenciu, Anca,Li, Jing Qi
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p. 116 - 127
(2007/10/03)
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- Tri(1-adamantyl)methane and its Thermolysis
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The synthesis of the title compound, a new tri(tert-alkyl)methane, and the kinetics and products of its thermolysis are described.
- Lomas, John S.
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p. 1531 - 1532
(2007/10/02)
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- Reductive Alkylation and Reduction of Tertiary, Secondary, and Benzylic Alcohols with Trimethyl-, Triethyl-, and Triisopropylboron/Trifluoromethanesulfonic (Triflic) Acid
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Tertiary, secondary, and benzylic alcohols were reductively alkylated and reduced with trimethyl-, triethyl-, and triisopropylboron/trifluoromethanesulfonic (triflic) acid.A postulated mechanism for the reactions is discussed.
- Olah, George A.,Wu, An-hsiang,Farooq, Omar
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p. 2759 - 2761
(2007/10/02)
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- Photochemistry of phenyl thioethers and phenyl selenoethers. Radical vs ionic behavior
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In analogy with alkyl iodides and bromides, the phenyt thio- and selenoethers 2a,b, 13a, 21b,c and 35 displayed competing radical and ionic photobehavior on irradiation in solution, via a mechanism thought to involve initial homolytic cleavage of the alkyl C-S or C-Se bond followed by electron transfer within the resulting radical pair cage (Scheme I). These are the first examples of ionic photobehavior to be recognized for the C-SAr and C-SeAr chromophores. The electronegatively substituted pentafiuorophenyl analogues 2c, 13b, and 21d displayed enhanced ionic photobehavior. By contrast, the 4-methoxyphenyl derivative 21a exhibited almost exclusively radical behavior. The sulfoxide (2R*,R*s)-21f displayed principally radical behavior, accompanied by epimerization at sulfur. The quantum yields for the disappearance of the 2-norbornyl ethers 21b and 21c were 0.53-0.64 in solution and rose to 0.89-0.95 in the presence of suspended fumed silica. Irradiation of the phenyl thioether 21b on silica gel resulted in nucleophilic trapping by surface silanol groups to afford covalently bound material (33), which afforded chloride 34 on treatment with SOCl2. Irradiation of phenyl thioethers 2a and 35, phenyl selenoether 2b, or C6H5SH in allyl alcohol solution afforded acetal 11, apparently via isomerization of some of the solvent to propanal (44) followed by acetalization. Irradiation of alcoholic solutions of aldehydes containing C6H5SH is a useful means of generating acetals under neutral conditions.
- Kropp, Paul J.,Fryxell, Glen E.,Tubergen, Mark W.,Hager, Michael W.,Harris Jr., G. Davis,McDermott Jr., T. Paul,Tornero-Velez, Rogelio
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p. 7300 - 7310
(2007/10/02)
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- Novel Rearrangement of 5,6-Disubstituted Bicyclooctan-2-ones with AlCl3. Application to Total Synthesis of (+/-)-5-Oxosilphiperfol-6-ene and (+/-)-Silphiperfol-6-ene
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The acid-catalyzed rearrangement of bi- and tricyclic cyclobutyl ketones 8-20 having a bicyclooctan-2-one moiety with AlCl3 was studied to elucidate the scope and limitations of the novel rearrangement by which the tricyclic ketone 1 gave the angul
- Kakiuchi, Kiyomi,Ue, Masaki,Tsukahara, Hiroshi,Shimizu, Toshihiro,Miyao, Tomoya,et al.
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p. 3707 - 3712
(2007/10/02)
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- Cross-Coupling Reaction of tert-Alkyl halides with Grignard Reagents in Dichloromethane as a Non-Lewis Basic Medium
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In dichloromethane as a non-Lewis basic solvent, 1-haloadamantane 1 underwent a cross-coupling reaction with Grignard reagents to give bridgehead-substituted products 3-16 in moderate yields.In this case the same kind of halogen in both 1 and a Grignard reagent was favored; if not, functional exchange (i.e., 1a to 1c) occurred first.The reaction using 5-hexenylmagnesium bromide as a radical probe afforded uncyclized/cyclized coupling products in a 6/4 ratio.These fact suggested the significant participation of the single-electron-transfer process in these reactions.The present method could be extended to tert-butylation with some Grignard reagents.Interestingly, 1,3-dichloro-3-methylbutane coupled with butylmagnesium chloride selectively at the tertiary position. for the above displacement reaction of 1, an organozinc was also found to be effective.
- Ohno, Masatomi,Shimizu, Kazuo,Ishizaki, Kenichi,Sasaki, Tadashi,Eguchi, Shoji
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p. 729 - 733
(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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- TRANSANNULAR IONIC HYDROGENATION, AND ACIDIC CYCLIZATION AND ISOMERIZATION REACTIONS OF 3,7-DIMETHYLENEBICYCLONONANE AND ITS DERIVATIVES
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The ionic hydrogenation, isomerization, and cyclization reactions of 3,7-dimethylenebicyclononane and related compounds have been studied.Ionic hydrogenation of the exocyclic methylene ?-bond occurs via the formation of alkyladamantanes.Reaction of 3,7-dimethylenebicyclononane with a chiral reagent results in the formation of an asymmetric adamantane derivative with an enantiomeric purity similar to that of the starting diene.
- Krasutskii, P. A.,Ambrosienko, N. V.,Rodionov, V. N.,Yurchenko, A. G.,Parnes, Z. N.,Bolestova, G. I.
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p. 1333 - 1337
(2007/10/02)
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- Selective Cleavage of Carbon-Nitrogen Bonds with Platinum
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The selective hydrogenolysis of carbon-nitrogen bonds relative to carbon-carbon bonds with a heterogeneous platinum catalyst is studied on a wide variety of nitrogen-containing organic molecules.Nitriles, secondary and primary amines, nitro compounds, heterocycles, and aromatic amides are cleanly converted to the parent hydrocarbon and ammonia in the gas phase with a platinum on silica catalyst and hydrogen.Aliphatic amides pass the catalyst unchanged.Unusual is the high platinum content of the catalyst (40percent) which proved to be essential for the catalytic activity reported.
- Guttieri, Mary J.,Maier, Wilhelm F.
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p. 2875 - 2880
(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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- ACID CATALYZED RING CONTRACTIONS IN ENDO-2,8-TRIMETHYLENE-CIS-BICYCLOOCTYL CATIONS TO METHYLPERHYDROTRIQUINACENES. ONE OF THE METHYL EXTRUSION PROCESSES IN THE TRICYCLOUNDECANE REARRANGEMENT
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Sulfuric acid catalyzed ring contractions with extrusion of a methyl group were examined for alcohol and olefin derivatives (28-31) of endo-2,8-trimethylene-cis-bicyclooctane (11), which was one of the two possible progenitors, among altogether 69
- Fujikura, Yoshiaki,Takaishi, Naotake,Inamoto, Yoshiaki
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p. 4465 - 4478
(2007/10/02)
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- TETRAMETHYLSILANE AS ALKYLATING AGENT IN REACTIONS WITH ALKYL HALIDES IN THE PRESENCE OF ALUMINIUM CHLORIDE AND ALUMINIUM BROMIDE
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A systematic investigation was undertaken into the electrophilic substitution of halogen atoms by a methyl group in alkyl halides by the action of tetramethylsilane and aluminium halides.It was established that the structure of the substrate has an effect on the reaction path.The methylation of primary alkyl halides is accompanied by isomerization of the carbon skeleton and leads to the production of saturated branched hydrocarbons.In the case of alkyl halides with a branched hydrocarbon chain difficultly obtainable hydrocarbons with a quarternary carbon atom are formed with high yields.The reaction takes place at room temperature in l0-l5 min.
- Bolestova, G. I.,Parnes, Z. N.,Latypova, F. M.,Kursanov, D. N.
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p. 1203 - 1208
(2007/10/02)
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- Hydrogenolysis of Alkyl-Substituted Adamantanes, Diamantanes, and Triamantanes in the Gas Phase on a Nickel-Alumina Catalyst
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Dealkylation of several alkyladamantanes, diamantanes, and triamantanes has been observed in the gas phase with hydrogen at atmospheric pressure on a 30percent nickel-alumina catalyst.Yield-temperature profiles show that the optimum temperature for obtaining the pure parent compound in high yield can be as low as 215 deg C.The ease of removal of an alkyl substituent depends on whether it is secondary or tertiary on the diamondoid nucleus.Rupture of the diamondoid skeleton requires much higher temperatures (over 280 deg C) than dealkylation.The hydrogenolytic degradation of diamantane to adamantane was examined with the aid of molecular mechanics calculations; likely pathways for C-C bond cleavage were deduced which are consistent with the several intermediates detected experimentally.The mechanism of dealkylation is discussed in terms of steric and thermodynamic factors and the nature of possible surface intermediates.*
- Grubmueller, Peter,Maier, Wilhelm F.,Raque Schleyer, Paul von,McKervey, M. Anthony,Rooney, John J.
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p. 1989 - 2006
(2007/10/02)
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