- Formal Bromine Atom Transfer Radical Addition of Nonactivated Bromoalkanes Using Photoredox Gold Catalysis
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Organic transformations mediated by photoredox catalysis have been at the forefront of reaction discovery. Recently, it has been demonstrated that binuclear Au(I) bisphosphine complexes, such as [Au2(μ-dppm)2]X2, are capable of mediating electron transfer to nonactivated bromoalkanes for the generation of a variety of alkyl radicals. The transfer reactions of bromine, derived from nonactivated bromoalkanes, are largely unknown. Therefore, we propose that unique metal-based mechanistic pathways are at play, as this binuclear gold catalyst has been known to produce Au(III) Lewis acid intermediates. The scope and proposed mechanistic overview for the formal bromine atom transfer reaction of nonactivated bromoalkanes mediated by photoredox Au(I) catalysis is presented. The methodology presented afforded good yields and a broad scope which include examples using bromoalkanes and iodoarenes.
- Zidan, Montserrat,McCallum, Terry,Swann, Rowan,Barriault, Louis
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supporting information
p. 8401 - 8406
(2020/11/03)
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- Asymmetric Synthesis of Carbocyclic Propellanes
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A modular synthesis of functionalized carbocyclic propellanes was developed. Formation of the first of two quaternary bridgehead centers has been achieved by desymmetrization of prostereogenic ketones by either Hajos-Parrish-Eder-Sauer-Wiechert-type processes or Werner’s catalytic asymmetric Wittig reaction. The obtained bicyclic enones were subjected to conjugate additions upon which the remaining ring was formed by olefin metathesis. All bridges are amenable to further derivatization, which renders those compounds useful as central units in fragment-based drug discovery or as ligand scaffolds.
- Schneider, Lisa M.,Schmiedel, Volker M.,Pecchioli, Tommaso,Lentz, Dieter,Merten, Christian,Christmann, Mathias
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supporting information
p. 2310 - 2313
(2017/05/12)
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- Structural and Electronic Noninnocence of α-Diimine Ligands on Niobium for Reductive C-Cl Bond Activation and Catalytic Radical Addition Reactions
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A d0 niobium(V) complex, NbCl3(α-diimine) (1a), supported by a dianionic redox-active N,N′-bis(2,6-diisopropylphenyl)-1,4-diaza-2,3-dimethyl-1,3-butadiene (α-diimine) ligand (ene-diamido ligand) served as a catalyst for radical addition reactions of CCl4 to α-olefins and cyclic alkenes, selectively affording 1:1 radical addition products in a regioselective manner. During the catalytic reaction, the α-diimine ligand smoothly released and stored an electron to control the oxidation state of the niobium center by changing between an η4-(σ2,π) coordination mode with a folded MN2C2 metallacycle and a κ2-(N,N′) coordination mode with a planar MN2C2 metallacycle. Kinetic studies of the catalytic reaction elucidated the reaction order in the catalytic cycle: the radical addition reaction rate obeyed first-order kinetics that were dependent on the concentrations of the catalyst, styrene, and CCl4, while a saturation effect was observed at a high CCl4 concentration. In the presence of excess amounts of styrene, styrene coordinated in an η2-olefinic manner to the niobium center to decrease the reaction rate. No observation of oligomers or polymers of styrene and high stereoselectivity for the radical addition reaction of CCl4 to cyclopentene suggested that the C-C bond formation proceeded inside the coordination sphere of niobium, which was in good accordance with the negative entropy value of the radical addition reaction. Furthermore, reaction of 1a with (bromomethyl)cyclopropane confirmed that both the C-Br bond activation and formation proceeded on the α-diimine-coordinated niobium center during transformation of the cyclopropylmethyl radical to a homoallyl radical. With regard to the reaction mechanism, we detected and isolated NbCl4(α-diimine) (6a) as a transient one-electron oxidized species of 1a during reductive cleavage of the C-X bonds; in addition, the monoanionic α-diimine ligand of 6a adopted a monoanionic canonical form with selective one-electron oxidation of the dianionic ene-diamido form of the ligand in 1a.
- Nishiyama, Haruka,Ikeda, Hideaki,Saito, Teruhiko,Kriegel, Benjamin,Tsurugi, Hayato,Arnold, John,Mashima, Kazushi
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p. 6494 - 6505
(2017/09/12)
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- Simple and high yield access to octafunctional azido, amine and urea group bearing cubic spherosilicates
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Spherosilicates and polyhedral oligomeric silsesquioxanes represent unique well-defined rigid building blocks for molecular and hybrid materials. Drawbacks in their synthesis are often low yields and the restricted presence of functional groups either based on incomplete transformation of all corners or the reactivity of the functional groups. Particularly amine-functionalization reveals some synthetic challenges. In this study we report the synthesis of a new class of octafunctionalized hydrogen bond forming spherosilicates via a facile route based on octabromo alkyl functionalized cubic spherosilicates. Four different alkyl chain lengths, namely C4, C5, C6 and C11, were realized starting from ω-alkenylbromides via hydrosilylation of Q8M8H. Using sodium azide in a mixture of acetonitrile:DMF = 10:1, the octaazide was obtained quantitatively and could be rapidly transformed in an octaamine cube via catalytic hydrogenation over Pd/C in absolute ethanol. The following reaction to hydrogen bond forming spherosilicates was performed in situ by adding propyl isocyanate. All transformations proceed quantitatively at the eight corners of the cube, which was evidenced by NMR spectroscopy and ESI-MS measurements. The Q8-target compound can be separated after each reaction step over simple chemical workup while no cage rearrangement was observed. The structures were confirmed using 1H, 13C, 29Si-NMR, FT-IR, elemental analysis and ESI-MS. The method opens a high yield route (overall isolated yield 83-88%) for structural building blocks in hybrid materials.
- Sch?fer, Sandra,Kickelbick, Guido
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supporting information
p. 221 - 226
(2016/12/28)
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- Production of ethylcycloalkanes bromomethylbiphenyl
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PROBLEM TO BE SOLVED: To provide a production method by which bromomethyl cycloalkanes can be easily obtained in an industrial scale.SOLUTION: A method for producing bromomethyl cycloalkanes comprises brominating cycloalkyl methanols by use of hydrogen bromide, wherein the reaction is carried out in the presence of an ionic liquid.
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Paragraph 0039-0041
(2018/10/16)
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- Cobalt-Mediated η5-Pentadienyl/Alkyne [5 + 2] Cycloaddition Reactions: Substitution Effects, Bicyclic Synthesis, and Photochemical η4-Cycloheptadiene Demetalation
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The preparation of seven-membered carbocycles via traditional organic synthesis is difficult, yet essential, due to the prevalence of these moieties in bioactive compounds. As we report, the Co-mediated pentadienyl/alkyne [5 + 2] cycloaddition reaction generates kinetically stable η2,η3-cycloheptadienyl complexes in high yield at room temperature, which isomerize to the thermodynamically preferred η5-cycloheptadienyl complexes upon heating at 60-70 °C. Here we describe an extended investigation of this reaction manifold, exploring substituent effects and extending the reaction to tandem cycloaddition/nucleophilic cyclizations, generating fused bicyclic compounds. We also describe a new high-yielding photolytic method for the decomplexation of organic cycloheptadienes from Co(I) complexes. Both C5Me5 (Cp?) and C5H5 (Cp) half-sandwich complexes are active in [5 + 2] cycloaddition with alkynes, with Cp? generally providing higher yields of cycloheptadienyl complexes. Cp cycloheptadienyl complexes, however, are resistant to thermal η2,η3 ' η5 isomerization. The reaction remains limited to open pentadienyl complexes incorporating substituents in the terminal (1 and 5) positions, except for the unsubstituted CpCo(η5-cycloheptadienyl)+ complex, which is modestly reactive. Incorporation of tethered latent nucleophiles allows cyclization onto the intermediate cycloheptadienyl cations, producing bicyclo[5.3.0]decadiene and bicyclo[5.4.0]undecadiene systems with complete diastereocontrol. A selection of intermediate complexes have been crystallographically characterized. Addition of tethered malonate nucleophiles occurs reversibly with equilibration to a thermodynamic elimination product, while enolate nucleophiles cyclize reliably under kinetic control. The resulting bicyclic products are decomplexed in high (>90%) yield by UV photolysis in the presence of allyl bromide to provide the organic bicyclic diene with complete retention of ring fusion geometry and without double-bond isomerization.
- Ylijoki, Kai E. O.,Kirk, Andrew D.,B?cklein, Sebastian,Witherell, Ross D.,Stryker, Jeffrey M.
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p. 3335 - 3357
(2016/01/15)
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- Cleavage of C-C and C-Si σ-bonds and their intramolecular exchange
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C-C and C-Si σ-bonds are cleaved to undergo bond exchange when substrates equipped with cyclobutanone and silacyclobutane moieties are treated with a palladium(0) catalyst. The skeletal exchange results in construction of silabicyclo[5.2.1]decanes in a diastereoselective manner.
- Ishida, Naoki,Ikemoto, Wataru,Murakami, Masahiro
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supporting information
p. 5912 - 5915
(2014/05/20)
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- Synthesis of 3-aza-bicyclo[3.1.0]hexan-2-one derivatives via gold-catalyzed oxidative cyclopropanation of N -allylynamides
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N-Allylynamides with various functional groups and different substitution patterns can be converted into 3-aza-bicyclo[3.1.0]hexan-2-one derivatives in moderate to high yield using IMesAuCl/AgBF4 as the catalyst and pyridine N-oxide as the oxidant. A noncarbene mediated approach is proposed as the mechanism.
- Wang, Kai-Bing,Ran, Rui-Qiao,Xiu, Shi-Dong,Li, Chuan-Ying
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supporting information
p. 2374 - 2377
(2013/06/27)
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- Synthesis and nmr spectra of tetrahydrofuran-2-13C
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An original method was developed for the synthesis of THF labeled selectively with the 13C isotope at the α-carbon atom. The effective reduction of symmetry brought about by the insertion of the isotopic label removes the excess degeneracy of the spin systems describing the multiplet structure of the 1H and 13C NMR spectra, making it possible to undertake a detailed analysis. Exact values for the 1H-1H spin-spin coupling constants through four bonds and also the 13C-1H and 13C-13C spin-spin coupling constants involving the ?-carbon atom were determined for the first time. The isotopic chemical shifts of the protons and 13C nuclei caused by replacement of the 12C nucleus by 13C were determined. These data can be used to construct a quantitative model of the conformational behavior of THF as a molecular system in which pseudorotation in terms of vibrations with large amplitude is realized.
- Chertkov,Shestakova,Chertkov
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p. 412 - 421
(2012/10/29)
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- Carbocationic n-endo-trig cyclizations
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Unsaturated benzyl cations (4-MeOC6H4)CH +-(CH2)n-CH=CH2 (1) have been generated laser-flash photolytically in acetonitrile in the presence of enol ethers or 2-methylfuran. The reactions of the cations 1 (n = 2 and 4) with these π-nucleophiles follow second-order rate laws with rate constants comparable to those of the analogous saturated species (4MeOC6H 4)CH+-(CH2)3CH3. Product studies show the absence of cyclization products. In contrast, the carbocation (4-MeOC6H4)CH+-(CH2) 3-CH=CH2 (Id) undergoes a highly reversible 6endo-trig cyclization which is approximately 107 times faster than the corresponding intermolecular reaction of (4MeOC6H4)CH +-(CH2)3CH3 with hex1-ene. This cyclization yields a highly electrophilic, partially bridged carbocation, which accounts for the finding that Id is consumed eight times faster in trifluoroethanol solution than all other carbocations of this series. Quantum-chemical calculations (B3LYP/6311G(d,p) and MP2/6-31+G(2d,p)) have been performed to elucidate the structures of the involved carbocations. Consequences of these findings on the role of π-participation in solvolysis reactions are discussed.
- Shi, Lei,Horn, Markus,Kobayashi, Shinjiro,Mayr, Herbert
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supporting information; experimental part
p. 8533 - 8541
(2010/03/26)
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- Rearrangement, nucleophilic substitution, and halogen switch reactions of alkyl halides over NaY zeolite: Formation of the bicyclobutonium cation inside the zeolite cavity
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Rearrangement and nucleophilic substitution of cyclopropylcarbinyl bromide over NaY and NaY impregnated with NaCl was observed at room temperature. The first-order kinetics are consistent with ionization to the bicyclobutonium cation, followed by internal return of the bromide anion or nucleophilic attack by impregnated NaCl to form cyclopropylcarbinyl, cyclobutyl, and allylcarbinyl chlorides. The product distribution analysis revealed that neither a purely kinetic distribution, similar to what is found in solution, nor the thermodynamic ratio, which favors the allylcarbinyl halide, was observed. Calculations showed that bicyclobutonium and cyclopropylcarbinyl carbocations are minimal over the zeolite structure, and stabilized by hydrogen bonding with the framework structure. A new process of nucleophilic substitution is reported, namely halogen switch, involving alkyl chlorides and bromides of different structures. The reaction occurs inside the zeolite pores, due to the confinement effects and is an additional proof of carbocation formation on zeolites. The results support the idea that zeolites act as solid solvents, permitting ionization and solvation of ionic species.
- Franco, Marcelo,Rosenbach Jr., Nilton,Ferreira, Glaucio B.,Guerra, Antonio C. O.,Kover, W. Bruce,Turci, Cassia C.,Mota, Claudio J. A.
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p. 1592 - 1600
(2008/09/18)
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- Synthesis of 2-arylcycloalka-2,4-dienones using sulfone-based methodology
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Addition of the anion derived from (phenylthiomethyl)phenyl sulfone to a selection of aryl ω-alkenyl ketones gives adducts that via a sequence of Lewis acid catalyzed rearrangement, α-allylation, and metathesis give rise to 2-thio-4-cycloalkenones. These in turn give cycloalkadienones upon oxidation and elimination. An attempt to develop a polymer-supported variant fails because of the reversibility of sulfone anion addition.
- Hok, Saphon,Schore, Neil E.
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p. 1736 - 1738
(2007/10/03)
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- Synthesis of C3-C9-alkenyl 2,3-unsaturated glucosides from glucose and some alkenols
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C3-C9-Alkenyl 2,3-unsaturated glucosides have been synthesized from glucose and C3-C9-alkenols by using Ferrier reaction with boron trifluoride etherate (BF3·Et2O) as Lewis acid catalyst in key step.
- Konstantinovic,Predojevic,Gojkovic,Ratkovic,Dimitrijevic,Mojsilovic
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p. 802 - 805
(2007/10/03)
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- Synthesis of Saturated Anacardic Acids, and Alkenyl and Alkynyl Analogues
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The C-alkylation of esters of 2-methoxy-6-methylbenzoic acid and of the 4-methyl isomers affords a route to homologous compounds including in the former case members of the natural anacardic acids from Anacardium occidentale and ω-alkynyl compounds suitable for synthesising other natural phenolic lipids or for structure/activity studies.
- Tyman, John H. P.,Visani, Naina
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p. 228 - 240
(2007/10/03)
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- Macrolactonization-Transannular Aldol Condensation Approach to the Taxane AB Ring System
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Cyclohexenone 13, containing the fully elaborated taxane A ring, was prepared from 4,4-dimethyl-2-cyclohexenone (43percent for four steps); two copper-catalyzed Grignard conjugate addition reactions on crowded dienones 8 and 11 were employed as key transformations.Elaboration of 13 to the chloro keto acid 6 was achieved via an epoxidation/regioselective chloride-mediated epoxide ring opening/Jones oxidation protocol (42percent for three steps).Macrolactonization (59percent) followed by chemoselective transannular aldol condensation within the resulting 11-membered bicyclic keto lactone 4 under thermodynamic control (51percent) resulted in closure of the taxane B ring to afford the target 2(5H)-furanone 3.
- Chai, Ki-Byung,Sampson, Paul
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p. 6807 - 6813
(2007/10/02)
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- Oxygenated alicyclic compounds and their use in perfumery
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A compound of formula STR1 wherein R1 represents a hydrogen atom or a saturated, linear or branched, alkyl radical, having from 1 to 4 carbon atoms, and R2 designates a lower alkyl radical, saturated or unsaturated, linear or branched; or any mixture containing a predominant amount of said compound (I), together with its isomer of formula STR2 wherein R1 and R2 are defined as above. Compounds (I) and their mixtures mentioned above develop odor notes of the woody-amber type and are therefore used as perfuming ingredients for the preparation of perfuming compositions and perfumed articles. A process for the preparation of compounds (I) and their mixtures is disclosed.
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- Homolytic Displacement at Saturated Carbon: Part 5. Synthesis of Cyclopropylmethyl, Bicyclohex-2-yl, Bicyclohept-2-yl and Cyclohexanespirocycloprop-2-yl Sulphones from the Corresponding But-3-enylcobaloximes
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But-3-enylcobaloxime reacts with arenesulphonyl chlorides under thermal and photochemical conditions to give cyclopropylmethyl sulphones.The yields depend upon the reaction conditions used.Similar reactions of cyclopent-2-enylmethylcobaloxime and cyclohex-2-enylmethylcobaloximes under photochemical conditions form a mixture of cis and trans isomers of bicyclohex-2-yl and bicyclohept-2-yl sulphones in (50:50) and (70:30) isomeric ratios respectively.However, cyclohex-3-enylcobaloximes form only the trans-bicyclohex-2-yl sulphone.Exclusive formation of cycloalkanespirocycloprop-2-yl sulphones is observed in the reactions of 2-(cyclo alk-1-enyl)ethylcobaloximes with arenesulphonyl chlorides.The reactions are free radical in nature and are believed to take place by a chain mechanism.In the key step a homolytic attack of the RSO2 radical at the terminal (δ) carbon of the butenyl ligand leads to the cyclized product.The exact nature of the ring closure step is uncertain, as both concerted and stepwise mechanisms are possible.
- Gupta, B. Dass,Das, Indira,Dixit, Vandana
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p. 2409 - 2446
(2007/10/02)
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- Surface Reactions, 9 / Dehydrohalogenation of Halohydrocarbons at Raney Nickel
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Raney nickel, a highly reactive and air-sensitive solid, if prepared and investigated under oxygen-free conditions, exhibits interesting catalytic properties.Using photoelectron spectroscopy for real-time gas analysis in a flow reactor, the following results are obtained with alkyl and acylhalides: Dehydrohalogenation temperatures are lowered relative to thermal HHal elimination up to 350 K.Monochloro and bromo propanes and butenes yield propene and butadiene, respectively. 1,1-Dichloro ethane or 1,1-dibromo propane only split off one HHal and form chloroethene or 1,1-bromopropene-2.HCl elimination from 2-methyl propionic acid chloride, expectedly, produces dimethyl ketene.Most interesting, however, is the ring opening of monobromo cyclobutane to 1-bromo-butene-3, observed already at room temperature, which strongly suggests the intermediate formation of a chemisorbed surface carbene at Raney nickel.The formation of hexadiene-1,5 as a by-product in the HCl elimination of 1-chloropropane, i.e. a surface carbene dimer, indicates their presence also in other dehydrohalogenations heterogeneously catalyzed by Raney nickel.
- Bock, Hans,Wolf, Hans Peter
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p. 699 - 714
(2007/10/02)
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- Oxygen permeable polymeric materials
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A polymer represented by the general formula STR1 where m is the average degree of polymerization of the polymer, y is an integer from 1 to 3, x is an integer from 1 to 10, A denotes a halogen atom and R denotes an alkyl radical with 1 to 6 carbon atoms.
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- Rate constants for abstraction of bromine from bromotrichloromethane by butyl, cyclopropylmethyl, and phenyl radicals in solution
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The radical chain decomposition of cyclopropylmethyl(1-hydroxy-1-methylethyl)diazene ((CH3)2C(OH)N=NCH2- 1) at 253-341 K in hexafluorobenzene or in dichloromethane solution containing bromotrichloromethane affords cyclopropylmethyl bromide, 4-bromo-1-butene, 1-bromo-5,5,5-trichloro-2-pentene, and 3,5-dibromo-1,1,1-trichloropentane from the cyclopropylmethyl portion of 1.Other major products are nitrogen, acetone, and chloroform.The rate constant for formation of cyclopropylmethyl bromide by attack of cyclopropylmethyl free radicals from 1 at bromine of BrCCl3 (kBrcpm) was calculated from the product composition using the known rate constant for rearrangement of cyclopropylmethyl radicals to 3-buten-1-yl radicals.At 25 deg C, kBrcpm = 6.5 x 1E8 M-1s-1 and the temperature dependence is given by log (kBrcpm/M-1s-1) = (10.6 +/- 0.3) - (2.4 +/- 0.4)/θ, where θ = 2.3RT kcal/mol-1.Non-chain decomposition of (CH3)2C(OH)N=N-R (2, R = Bu, and 3, R = Ph) in the presence of excess 1,1,3,3-tetramethylisoindolin-2-yloxyl (4) and bromotrichloromethane afforded BuBr and PhBr, respectively, in yields determined by the relative concentrations of 4 and BrCCl3.Rate constants for coupling (kc) of Bu. and Ph. with 4 were assumed to be proportional to rate constants for diffusion controlled reactions, kd, which were estimated from measured viscosities.Values of kBrBu and kBrPh, calculated from kc and product yields for reactions at 80 deg C, are 0.26 x 1E9 and 1.55 x 1E9 M-1s-1, respectively.The relative radical reactivities toward BrCCl3 at 80 deg C are Ph, 6; cpm, 5; Bu, 1.
- Mathew, Lukose,Warkentin, John
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- Absolute Rate Constants for Bromine Abstraction from N-Bromoimides and Br2 by Alkyl Radicals
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Imidyl radicals react with cyclopropanes solely via hydrogen abstraction.In the case of methylcyclopropane, the major product (cyclopropylcarbinyl bromide) is derived from abstraction of hydrogen from the methyl group.The resultant cyclopropylcarbinyl radical is partioned between two pathways: (1) abstraction of Br from N-bromoimide and (2) rearrangement to the allylcarbinyl radical (eventually yielding 4-bromo-1-butene).Since the absolute rate of the rearrangement is known, an absolute rate constant for the abstraction of Br from N-bromoimides by alkyl radicals can be derived (CH2Cl2 solvent, 15 deg C), k ca. (1.3-1.6)1xE10 M-1s-1.Reactions carried out in the presence of Br2 provide a third pathway for scavenging of the cyclopropylcarbinyl radical, providing kBr2=2.2x1E10 M-1s-1.Thus, trapping of primary R. by either N-bromoimides or Br2 occurs at rates that are diffusion-controlled.
- Tanko, James M.,Skell, Philip S.,Seshadri, Sri
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p. 3221 - 3225
(2007/10/02)
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- FREE RADICAL REARRANGEMENTS OF ORGANOCOBALOXIMES: ALKYNYL TO CYCLOALKYLIDENE AND HEXENYL TO CYCLOPENTYLMETHYL
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Under irradiation by tungsten light in pyridine solution, several substituted alkylcobaloximes undergo rearrangement to more stable substituted alkyl- or alkenyl-cobaloximes.When the same reactions are carried out in the presence of carbon tetrachloride or chloroform, no rearranged organobaloximes are obtained, but a variety of organic products are obtained derived from the interception of transient organic radicals by the halogenated solvent.The rearrangements are rationalised in terms of a reversible homolysis of the carbon-cobalt bond, rearrangement of the organic radical and recapture by the cobalt(II) fragment to give complexes that are more stable to irradiation than their precursors.
- Bougeard, Peter,Cooksey, Christopher J.,Johnson, Michael D.,Lewin, Melanie J.,Mitchell, Stewart,Owens, Paul A.
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p. 349 - 358
(2007/10/02)
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- EPOXIDES AS ALKENE PROTECTING GROUPS. A MILD AND EFFICIENT DEOXYGENATION
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Dimethyl diazomalonate smoothly deoxygenates epoxides to alkenes with rhodium(II) acetate catalysis.
- Martin, Michael G.,Ganem, Bruce
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p. 251 - 254
(2007/10/02)
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- Selectivity and Reactivity in Some Oxidations with Pentavalent and Hexavalent Chromium Reagents: A Short Synthesis of Norbisabolide
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Selective oxidative cyclization of the t-hydroxyolefin (5) with pyridinium chlorochromate leads to a simple synthesis of norbisabolide (4).On the other hand, α-terpineol (7) on treatment with chromium(V) reagent undergoes facile oxidative cleavage followed by cyclization to give homoterpenyl methyl ketone (8).
- Kuchibhotla, Uma,Chakraborty, T. K.,Chandrasekaran, S.
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p. 1216 - 1218
(2007/10/02)
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- FORMATION OF SULFUR COMPOUNDS IN THE HYDRODENITROGENATION OF PIPERIDINE, PYRIDINE, 1-PENTYLAMINE AND 1-PENT-4-ENYLAMINE ON A NICKEL-TUNGSTEN CATALYST IN THE PRESENCE OF HYDROGEN SULFIDE
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Hydrogenations of piperidine, pyridine, 1-pentylamine, and 1-pent-4-enylamine were carried out in an autoclave at 300 deg C on a sulfidized nickel-tungsten catalyst using either pure hydrogen or a mixture of hydrogen with hydrogen sulfide.Hydrogen sulfide was found to raise the degree of conversion of the starting substances and accelerate the hydrodenitrogenation by formation of sulfur compounds; 1-pentanethiol, di(1-pentyl)sulfide, 2-methylthiacyclopentane, thiacyclohexane and other sulfur compounds were detected in the reaction mixtures in the presence of hydrogensulfide.A reaction pathway is suggested of the hydrodenitrogenation of piperidine in the presence of hydrogen sulfide, accounting for the favourable effect of the latter on the hydrodenitrogenation of nitrogen compounds.
- Cerny, Mirko
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p. 928 - 935
(2007/10/02)
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