- Molecule-induced alkane homolysis with dioxiranes
-
The mechanisms of C-H and C-C bond activations with dimethyldioxirane (DMD) were studied experimentally and computationally at the B3LYP/6-311+G**//B3LYP/6-31G* density functional theory level for the propellanes 3,6-dehydrohomoadamantane (2) and 1,3-dehydroadamantane (3). The σC-C activation of 3 with DMD (ΔG? = 23.9 kcal mol-1 and ΔGr = -5.4 kcal mol-1) is the first example of a molecule-induced homolytic C-C bond cleavage. The C-H bond hydroxylation observed for 2 is highly exergonic (ΔGr = -74.4 kcal mol-1) and follows a concerted pathway (ΔGr = 34.8 kcal mol-1), in contrast to its endergonic molecule-induced homolysis (ΔG? = 28.8 kcal mol-1 and ΔGr = +9.2 kcal mol-1). The reactivities of 2 and 3 with CRO2Cl2, which follow a molecule-induced homolytic activation mechanism, parallel the DMD results only for highly reactive 3, but differ considerably for more stable propellanes such as 4-phenyl-3,6-dehydrohomoadamantane (1) and 2.
- Fokin,Tkachenko,Korshunov,Gunchenko,Schreiner
-
-
Read Online
- A facile synthesis of 7-methylenebicyclo[3.3.1]nonan-3-one and its transformation leading to the novel tricyclic system, protoadamantane
-
A practical synthesis of 7-methylenebicyclo[3.3.1]nonan-3-one 2 by the fragmentation of 1,3-adamantanediol 8, which was prepared effectively by the ruthenium-catalyzed oxyfunctionalization of 1-adamantanol 7, is described. Characteristic transannular cyclization of 2 leading to a novel tricyclic system, 1-hydroxy-4-protoadamantanone 9, via the corresponding exo-epoxide 10 is also presented.
- Muraoka,Wang,Okumura,Nishiura,Tanabe,Momose
-
-
Read Online
- Oxa-adamantyl cannabinoids
-
As a continuation of earlier work on classical cannabinoids bearing bulky side chains we report here the design, synthesis, and biological evaluation of 3′-functionalized oxa-adamantyl cannabinoids as a novel class of cannabinergic ligands. Key synthetic steps involve nucleophilic addition/transannular cyclization of aryllithium to epoxyketone in the presence of cerium chloride and stereoselective construction of the tricyclic cannabinoid nucleus. The synthesis of the oxa-adamantyl cannabinoids is convenient, and amenable to scale up allowing the preparation of these analogs in sufficient quantities for detailed in vitro evaluation. The novel oxa-adamantyl cannabinoids reported here were found to be high affinity ligands for the CB1 and CB2 cannabinoid receptors. In the cyclase assay these compounds were found to behave as potent and efficacious CB1 receptor agonists. Isothiocyanate analog AM10504 is capable of irreversibly labeling both the CB1 and CB2 receptors.
- Ho, Thanh C.,Tius, Marcus A.,Nikas, Spyros P.,Tran, Ngan K.,Tong, Fei,Zhou, Han,Zvonok, Nikolai,Makriyannis, Alexandros
-
supporting information
(2021/03/14)
-
- Aerobic oxidative synthesis of benzimidazoles from amines catalyzed by 3-methyl-4-oxa-5-azahomoadamantane and iron(III) chloride
-
A simple and efficient catalytic system including 3-methyl-4-oxa-5- azahomoadamantane and FeCl3 for aerobic oxidative synthesis of benzimidazoles from primary amines and o-phenylenediamine is presented. This process uses O2 as economic and green oxidant and water as green solvent, tolerates a wide range of substrates, and can afford the target products in moderate to excellent yields.
- Yu, Jiatao,Lu, Ming
-
p. 10017 - 10025
(2016/01/12)
-
- 2-Azaadamantane N-oxyl (AZADO) and 1-Me-AZADO: Highly efficient organocatalysts for oxidation of alcohols
-
Development of a stable nitroxyl radical class of catalysts, 2-azaadamantane N-oxyl (AZADO) and 1-Me-AZADO, for highly efficient oxidation of alcohols is described. AZADO and 1-Me-AZADO exhibit superior catalytic proficiency to TEMPO, converting various sterically hindered alcohols to the corresponding carbonyl compounds in excellent yields. Copyright
- Shibuya, Masatoshi,Tomizawa, Masaki,Suzuki, Iwao,Iwabuchi, Yoshiharu
-
p. 8412 - 8413
(2007/10/03)
-
- Method for producing 1,3-adamantanediol
-
[PROBREM TO BE SOLVED]: It is a method of important as the raw material that synthesizes various Ada man tongue conductors including the fine polymer, and manufacturing useful 1 and three-Adamantangeorl as various coating materials, and offer the method of efficiently manufacturing a target thing from the reaction under the normal pressure that makes 1 and three-Ge halogenation Ada man tongues a raw material. [SOLUTION]: "1,3-adamantanediols precursor" such as 3-halogenated 1-formyladamantanes etc. is obtained by mixing and reacting 1,3-dihalogenated adamantanes with formic acid, formate salt or metal oxide, then the precursor is mixed and reacted with water to convert to 1,3-adamantanediols.
- -
-
Page/Page column 9-10; 13-14
(2008/06/13)
-
- Regioselectivity on electroreductive transannular reaction of 7-methylenebicyclo[3.3.1]nonan-3-one
-
A competitive transannular reaction occurred to give 7-methyltricyclo[3.3.1.03.7]nonan-3-ol (5) and 1-adamantanol (6) in the non-mediated electroreduction of 7-methylenebicyclo[3.3.1]nonan-3-one (1) in N,N-dimethylformamide. The apparent temperature dependence of the regioselectivity of the reaction may be attributed to the competitive operation of both kinetic and thermodynamic controls in the cyclization of the ketyl radical anion. The differences in the parameter of activation between the 5-exo- and 6-endocyclizations of 1,? ,ΔΔH?(5-exo - 6-endo) and ΔΔS?(5-exo - 6-endo), were evaluated to be -3.1 kcal mol-1 and -11 cal mol-1 K-1, respectively. Semiempirical PM3 (RHF and UHF) calculations were also carried out to elucidate the reaction mechanism.
- Itoh,Kato,Unoura,Senda
-
p. 339 - 345
(2007/10/03)
-
- Radical Rearrangements for the Chemical Vapor Deposition of Diamond
-
A combination of chemical trapping and computations is used to determine the activation parameters for the interconversion of the 3-methylenebicyclo[3.3.1]nonan-7-yl (1), (3-noradamantyl)methyl (2), and 1-adamantyl (3) radicals. The three radicals model proposed intermediate surface radical structures in the chemical vapor deposition (CVD) of diamond on its 2 × 1 reconstructed [100] surface. The study finds that relatively low-level calculations previously applied to the problem of diamond growth are reliable, at least qualitatively.
- Mueller, Andreas M.,Chen, Peter
-
p. 4581 - 4586
(2007/10/03)
-
- Investigations on Transition-State Geometry in the Aldol Condensation
-
Model compounds 1 and 2 have been studied to elucidate the relative orientation of enolate and carbonyl moieties in the aldol reaction. The syntheses of these compounds have been achieved from a common precursor derived from fragmentation of adamantane. Models of the limiting transition structures reveal that the cyclization must proceed through either a synclinal or antiperiplanar orientation of the aldehyde with respect to the enolate. Cyclizations of 1 were unexpectedly sluggish due to slow deprotonation of the tertiary center. The cyclization of 2 was very rapid and was studied as a function of enolate type (metal counterion), base type, solvent, and additive. The reactions of metal enolates showed an increasing preference for the syn product 5 with increasing cation coordinating ability (K+ + + +). Attempted cyclization via boron and stannous enolates failed. The type of base and the choice of solvent had negligible effects on the selectivity. However, in the presence of strong cation-complexing agents, the model showed a strong preference for reaction via an antiperiplanar orientation of reactants giving the anti product 6 with high selectivity. The origin of the selectivities and the implication for enolate and transition structures are discussed.
- Denmark, Scott E.,Henke, Brad R.
-
p. 2177 - 2194
(2007/10/02)
-
- Trigonal-Bipyramidal Five-Coordinate Trisolefin Complexes of Platinum(II)
-
Five-coordinate trigonal-bipyramidal platinum(II) becomes the ground-state geometry in the presence of the chelating diolefin 3,7-dimethylenebicyclo[3.3.1]nonane [DMBN]. Anionic σ donors invariably take up the axial positions, and the third trigonal position is generally held by a π donor-acceptor. These trigonal-bipyramidal complexes are inert to addition at the platinum center, but will react by dissociation of the third trigonal ligand. As long as the dissociative pathway is prohibited (e.g. by addition of excess olefin) the complexes are quite stable, and in particular do not react via. σ group migration to coordinated olefin. The prototypic complex [(C2H4)(DMBN)PtIICl2] crystallizes in the space group P21/c, a = 7.629 (1) A?, b = 12.431 (1) A?, c = 14.714 (2) A?, and β = 100.88 (1)°. The trigonal-bipyramidal structure has C2v geometry with the 2-fold axis passing through the Pt atom and ethylene midpoint. The mirrors are respectively parallel and perpendicular to the trigonal plane. A final R factor of 2.6% was obtained based on 3126 3σ reflections observed of 3990 unique reflections collected at -79?C. Replacement of one axial chloride by a methyl group greatly enriches the NMR spectra due to removal of the 2-fold axis and one mirror and allows for detailed analysis of the solution structure as well as for the observation of dynamic process(es) related to ethylene dissociation.
- Mink, Larry,Rettig, Michael F.,Wing, Richard M.
-
p. 2065 - 2071
(2007/10/02)
-
- Transmission of Polar Substituent Effects in Saturated Systems: Synthesis and 19F NMR Study of 3-Substituted Adamant-1-yl Fluorides
-
An extensive series of 3-substituted adamant-1-yl fluorides (3) covering a diverse range of substituents has been synthesized and characterized and the 19F chemical shifts measured.By use of multiple linear regression analysis, it is revealed that there i
- Adcock, William,Kok, Gaik B.
-
p. 356 - 364
(2007/10/02)
-
- Herstellung und Solvolyse von 3-substituierten p-Toluolsulfonsaeure-(1-adamantyl)estern
-
Methods for the preparation of some hitherto unknown 3-substituted 1-adamantyl toluenesulfonates are evaluated.Their solvolysis products in dioxane/water 70:30 are reported.
- Bielman, Rolf,Grob, Cyril A.,Schaub, Bruno
-
p. 1728 - 1733
(2007/10/02)
-
- Polar Effects. X. Polar Substituent Effects in the Solvolysis of 3-Substituted 1-Adamantyl Bromides and Tiluenesulfonates
-
The rate constants for 3-substituted adamantyl p-toluenesulfonated 3a-3k in ethanol/water 80:20 correlate well with the respective inductive subsitutent constants ?qI.The reaction constant ρ for the toluenesulfonates 3 is 10percent karger than for the corresponding bromides 2, indicating somewhat more charge separation in the activation of the toluenesulfonates.Evidence is presented that stabilization of the resultant 1-adamantyl cations by induction involves graded 1,3-bridging, which is favored when the subsituent is an electrofugal group, and that stabilization by n-electron donors involves C,C-hyperconjugation.Rate ratios for the toluenesulfonates 3 and the bromides 1 exceed 1E3 and are almost independent of the 3-subsituents.The implications of this are discussed in the light current hypotheses.
- Grob, Cyril A.,Schaub, Bruno
-
p. 1720 - 1727
(2007/10/02)
-