- Catalytic Ketone Hydrodeoxygenation Mediated by Highly Electrophilic Phosphonium Cations
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Ketones are efficiently deoxygenated in the presence of silane using highly electrophilic phosphonium cation (EPC) salts as catalysts, thus affording the corresponding alkane and siloxane. The influence of distinct substitution patterns on the catalytic effectiveness of several EPCs was evaluated. The deoxygenation mechanism was probed by DFT methods.
- Mehta, Meera,Holthausen, Michael H.,Mallov, Ian,Pérez, Manuel,Qu, Zheng-Wang,Grimme, Stefan,Stephan, Douglas W.
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p. 8250 - 8254
(2015/07/07)
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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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- 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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- 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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- 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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- Acid catalyzed ring contractions in endo-2,8-trimethylene-cis-bicyclo[.3.0]octyl cations to methylperhydrotriquinacenes. One of the methyl extrusion processes in the tricycloundecane rearrangement
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ABS Salfuric acid catalyzed ring contractions with extrusion of a methyl group were examined for alcohol and olefin derivatives (28-31) of endo-2,8-trtmethylene-cis-bicyclo[3.3.0]octane (II), which was one of the two possible progenitors, among altogether 69 isomers, for methylperhydrotriquinacenes (6, 7 and 12), the only methyltricyclodecane intermediates found so far, in the tricyctoundecane rearrangement. Only minor amounts (1.6-2.0%) of metthylperhydrotriquinacenes were formed from these reactants 28-31, and the results support the earlier theoretical conclusion that the methyl extrusions were in general energetically quite unfavorable processes owing to the formation of primary carbinyl cations at the expense of more stable secondary bridge or tertiary bridgehead ones. Reaction pathways for these precursors 28-31 were discussed with reference to those of perhydrotriquinacene 2-carbinyl cations (33a's), which corresponded to some of the ring contraction product cations from 28-31.
- Fujikura, Yoshiakl,Takaishi, Naotake,Inamoto, Yoshiaki
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p. 4465 - 4477
(2015/01/08)
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- Acid catalyzed ring contractions in endo-2,8-trimethylene-cis-bicyclo[3.3.0]octylcations 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-bicyclo[3.3.0]octane (11), which was one of the two possible progenitors, among altogether 69 isomers, for methylperhydrotriquinacenes (6, 7 and 12), the only methyltricyctodecane intermediates found so far, in the tricycloundecane rearrangement. Only minor amounts (1.6-2.0%) of methylperhydrotriquinacenes were formed from these reactants 28-31, and the results support the earlier theoretical conclusion that the methyl extrusions were in general energetically quite unfavorable processes owing to the formation of primary carbinyl cations at the expense of more stable secondary bridge or tertiary bridgehead ones. Reaction pathways for these precursors 28-31 were discussed with reference to those of perhydrotriquinacene 2-carbinyl cations (33a's), which corresponded to some of the ring contraction product cations from 28-31.
- Fujikura, Yoshiaki,Takaishi, Naotake,Inamoto, Yoshiaki
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p. 4465 - 4477
(2014/12/10)
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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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