- THE SOLVOLYSIS OF 1- AND 3-HOMOADAMANTYL-P-NITROBENZOATES IN ACETONITRILE-WATER (70:30 by weight)
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The solvolysis rates of t.butyl, 1-adamantyl, 3- and 1-homoadamantyl-p-nitrobenzoates in acetonitrile-water (70:30 by weight) are reported and the relative rates are discussed.These are the first solvolysis constants for 1- or 3-homoadamantyl esters of definitely known structure.
- Mergelsberg, Ingrid,Ruechardt, Christoph
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- 1,2-Methanoadamantane: A Molecule with a Twist Bent ? Bond
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The reaction of 1-(chloromethyl)-2-bromoadamantane with sodium leads to ring closure to the hitherto unknown 1,2-methanoadamantane (1).Reactivity studies of 1 provide strong evidence for the existence of a twist bent ? bond.
- Mlinaric-Majerski, Kata,Kaselj, Mira
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- Solvent-equilibrated ion pairs from carbene fragmentation reactions
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[R+ OC Cl-] ion pairs were generated in methanol/dichloroethane solutions, with R+ as the 1-bicyclo[2.2.2]octyl, 1-adamantyl, or 3-homoadamantyl cation. Ion pairs were produced either by the direct fragmentation of alkoxychlorocarbenes (ROCCl), with R = 1-bicyclo[2.2.2]octyl, 1-adamantyl, or 3-homoadamantyl, or by the ring expansion-fragmentation of R′CH2OCCl, with R′ = 1-norbornyl, 3-noradamantyl, or 1-adamantyl. Correlations of the [ROMe]/[RCl] product ratios as a function of the mole fraction of MeOH in dichloroethane showed that the homoadamantyl chloride ion pairs, produced by either the direct or ring expansion-fragmentations, were identical, solvent- and anion -equilibrated, and precursor independent. Laser flash photolysis experiments gave 20-30 ps as the time required for solvent equilibration and precursor independence. Methanol/chloride selectivities of the (less-stable) 1-adamantyl chloride and 1-bicyclo[2.2.2]octyl chloride ion pairs were not independent of their ROCCl or R′CH2OCCl precursors. Computational studies provided transition states for the fragmentations and for the structures of the ion pairs.
- Moss, Robert A.,Zheng, Fengmei,Fede, Jean-Marie,Johnson, Lauren A.,Sauers, Ronald R.
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- The Barbier Synthesis: A One-Step Grignard Reaction?
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Counter to generally accepted theory, it is demonstrated that the Byrbier synthesis does not necessarily involve the in situ formation of an organometallic compound.In certain cases, there is a radical pathway in which the anion radical (R.-X-) resulting from the attack by a halogenated derivative on lithium is directly trapped by the ketone or by the ketyl radical on the metal surface befor the organometallic compound forms.This pathway can be unique, as when 1-bromoadamantane condenses with adamantanone or hexamethylacetone.However, by extension of the Barbier synthesis to other "cage-structure" compounds homologous to adamantane, it is seen that the radical pathway can compete with the organometallic pathway and that this competition is principally determined by the stability of the cage radicals generated at the metal-solution interface.An optimum yield can be attained in this type of synthesis by choosing the Grignard reaction or the Barbier reaction, depending on the nature of the halogenated cage derivatives in use.
- Molle, Gerard,Bauer, Pierre
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- Chemoselectivity of Nitroxylation of Cage Hydrocarbons
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Abstract: The composition of reaction mixtures obtained by nitroxylation of 13 cage hydrocarbons with 100% nitric acid and its mixtures with acetic acid, acetic anhydride, and methylene chloride has been studied. More reactive substrates react with lowest
- Ivleva, E. A.,Klimochkin, Yu. N.,Leonova, M. V.
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p. 1702 - 1710
(2020/12/01)
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- One-pot synthesis of cage alcohols
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An efficient one-pot procedure has been developed for the synthesis of cage alcohols with hydroxy groups in the bridgehead positions. The procedure includes initial nitroxylation with nitric acid or a mixture of nitric acid with acetic acid and subsequent hydrolysis in the presence of urea.
- Klimochkin, Yu. N.,Yudashkin,Zhilkina,Ivleva,Moiseev,Oshis, Ya. F.
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p. 971 - 976
(2017/09/07)
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- SYNTHESIS AND HYDROLYTIC TRANSFORMATIONS OF NITROXY DERIVATIVES OF HOMOADAMANTANE PROTOADAMANTANE AND BICYCLONONANE
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Mono- and dinitroxy derivatives of homoadamantane, protoadamantane, and bicyclononane were synthesized by nitroxylation.A study was carried out on the reactivity of these hydrocarbons relative to nitric acid and the hydrolytic transformations of the products obtained.The acid-catalyzed skeletal rearrangement of 3,6-dinitroxyhomoadamantane to 3-nitroxymethyl-1-adamantanol proceeds with retention of the substituent at the carbon atom, at which the carbenium ion is generated.
- Klimochkin, Yu. N.,Zhilkina, E. O.,Abramov, O. V.,Moiseev, I. K.
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p. 1126 - 1131
(2007/10/02)
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- Relative Reactivity of Bridgehead Adamantyl and Homoadamantyl Substrates from Solvolyses with Heptafluorobutyrate as a Highly Reactive Carboxylate Leaving Group. Absence of SN2 Character of Solvolysis of tert-Butyl Derivatives
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Heptafluorobutyrates, conveniently prepared from alcohols, possess a reactivity similar to that of halides in solvolysis reactions.A product and isotope distribution study for the reaction of 1-adamantyl heptafluorobutyrate (1a) in 80:20 ethanol-H2(18)O demonstrated exclusive alkyl-oxygen cleavage.The reactivities of 1a, 1-(2a), and 3-homoadamantyl heptafluorobutyrate (3a) increase with the flexibility of the hydrocarbon skeleton.The rate constants are linearly correlated with the strain increase upon ionization.No acceleration attributable to nucleophilic solvent assistance was evidenced for the tert-butyl ester, 4a.A literature proposal for such assistance in solvolyses of 4 is examined.The existing data are explained better by an SN1 process with electrophilic assistance of the leaving group in the solvents that can form very strong hydrogen bonds.
- Farcasiu, Dan,Jaehme, Joachim,Ruechardt, Christoph
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p. 5717 - 5722
(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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- Competitive and Regiospecific Bridgehead Substitution in Electrophilic Oxidation Reactions of Homoadamantane
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Oxidation of homoadamantane with chromic acid, lead tetraacetate, p-nitroperbenzoic acid, or bromine occurs by competitive attack at the C-3 (major) and C-1 (minor) bridgehead positions.In striking contrast, dry ozonation of homoadamantane adsorbed on silica gel leads to regiospecific substitution at the chemically equivalent C-3 and C-6 bridgehead positions.A consequence of this observation is that some 1,3- and 3,6-disubstituted homoadamantanes can be prepared by dry ozonation of suitably substituted homoadamantane derivatives.
- Israel, Robert J.,Murray, Roger K.
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p. 4701 - 4705
(2007/10/02)
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- The Isomerisation of Homoadamantane-3-carboxylic Acid into Homoadamantane-1-carboxylic Acid
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It is shown by D-, 13C-, and double labelling experiments that the title isomerisation 2 -> 3 under Koch-Haaf conditions is due to reversible decarbonylation followed by intermolecular hydride transfer between the bridgehead positions of the two bridgehead homoadamantane cations and homoadamantane derivatives.The isomerisation is accompanied by complete equilibration of an isotopically labelled methylene group over all possible positions.This is due to the known adamantylmethyl-3-homoadamantyl cation rearrangement which is likewise occuring.In contrast to hydride transfer reactions in the adamantyl system the methylene groups of the homoadamantyl system are not participating in the hydride transfer between the bridgehead positions.
- Langhals, Heinz,Mergelsberg, Ingrid,Ruechardt, Christoph,Burger, Ulrich
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p. 1509 - 1524
(2007/10/02)
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- Formation of (1-adamantylcarbinyl)arenes from 3-azidohomoadamantane-aluminum chloride-aromatic substrates
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Reaction of 3-azidohomoadamantane with aromatic substrates catalyzed by aluminum chloride at 80 °C gave the corresponding (1-adamantylcarbinyl)arene in >90% yield. The reaction proceeds exclusively with elimination of azide ion. Competitive reaction with toluene (T)-benzene (B) gave an average kT/kB of ～14/1. The results indicate that a straightforward primary cation is probably not the actual attacking electrophile. The possible intervention of a bridged ion is discussed.
- Margosian, Daniel,Speier, Jon,Kovacic, Peter
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p. 1346 - 1350
(2007/10/02)
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