3047-21-0Relevant academic research and scientific papers
An Efficient Electrochemical Coupling of Allylic Halides by Using a Copper Anode
Tokuda, Masao,Endate, Kazuhiro,Suginome, Hiroshi
, p. 945 - 948 (2007/10/02)
A new electrolytic method for an efficient coupling of allylic halides by the use of a copper anode and a platinum cathode in the precence of sodium iodide is described.A method which avoids a loss of the copper anode owing to dissolution is also described.
Reductive Dimerization of Allyl and Benzyl Halides in Pb/n-Bu4NBr-DMF and PbBr2/Al-DMF Systems
Tanaka, Hideo,Yamashita, Shiro,Toru, Sigeru
, p. 1951 - 1953 (2007/10/02)
Reductive dimerization of allyl and benzyl halides has been performed by treatment with Pb/n-Bu4NBr and catalytic PbBr2/Al in N,N-dimethylformamide.
On the Mechanism of the Thermal Rearrangement of Bicyclohexane: Dispirohexane-3',1''-cyclopropane> and Analogously Substituted Derivatives as New Model Compounds
Kaufmann, Dieter,Meijere, Armin de
, p. 3134 - 3150 (2007/10/02)
Upon thermolysis the 2,3-diazabicyclooct-2-enes 10a-c yield only the thermodynamically more stable 1,5-hexadienes, namely 11, 13, and 15, respectively.Upon photolysis, however, remarkable proportions of the new bicyclohexane derivatives 2 (66percent), 4 (29percent), and 3 (58percent), respectively, are formed besides the hexadienes; the by-product (2percent) from 10a most probably is the hexalin 12, as it would arise from an intermediate diradical by neighboring group participation of both three-membered rings.The thermolyses of 2, 3, and 4 follow first order rate laws and yield 11, 13, and 15.According to the kinetic data, which best fit a two-step mechanism, the diradical from 2 is stabilized purely electronically by 25.8 kJ/mol with respect to the diradical from 4.
On the Influence of Substituents on the Cope Rearrangement of 1,5-Hexadienes: Cyclopropyl- and Methyl-substituted Model Systems
Kaufmann, Dieter,Meijere, Armin de
, p. 1128 - 1138 (2007/10/02)
The new 1,5-hexadiene derivatives 1 and 2 are obtained along with all other conceivable products upon methylenation of 1,2,6,7-octatetraene (5); 2 is also accessible from succindialdehyde and cyclopropylidenetriphenylphosphorane.The thermal rearrangements of 1 and 2 both proceed like that of 5 in two steps via 1,4-cyclohexadiyls, 1 yielding 3 and 19, 2 only 4.The distinct differences in the gas phase kinetic parameters for 2 and 15 (ln k(2) = 22.0-26200/RT and ln k(15) = 29.1-33300/RT, respectively) indicate the change in mechanism of the Cope rearrangement from concerted (for 15) to stepwise (for 2), apparently due to the cyclopropyl substituent effects.Upon sensitized irradiation of 2 the new hydrocarbons 24, 25, and 27 are formed, whereas nickel(0)-catalyzed rearrangement of 2 yields 25 exclusively.
CARBON-CARBON BOND FORMATION WITH METALLIC MANGANESE
Hiyama, Tamejiro,Sawahata, Miwa,Obayashi, Michio
, p. 1237 - 1238 (2007/10/02)
Metallic manganese is found to reduce allylic bromides and achieve the Barbier-type carbonyl addition of allyl unit.
New Method for Coupling Allylic Halides: Use of Te2- Species
Clive, Derrick L.J.,Anderson, Paul C.,Moss, Neil,Singh, Alok
, p. 1641 - 1647 (2007/10/02)
A variety of allylic halides were treated with Te2- (generated in situ) to afford coupled 1,5-dienes (average yield 78percent for 11 examples).Mechanistic studies establish that bisallylic tellurides are produced, and these decompose into allylic radicals which then dimerize.
Highly Selective Carbon-Carbon Bond Forming Reactions Mediated by Chromium(II) Reagents
Hiyama, Tamejiro,Okude, Yoshitaka,Kimura, Keizo,Nozaki, Hitosi
, p. 561 - 568 (2007/10/02)
A low valent chromium reagent is generated from chromium(III) chloride and a half mol of lithium aluminum hydride in tetrahydrofuran.The reagent behaves similarly to anhydrous chromium(II) chloride, which is commercially available, and reduces allylic halides to produce unisolable allylchromium species which add efficiently to aldehydes or ketones with high degree of stereo- and chemoselectivity.Particularly, high threo selectivity is observed in the reaction of aldehydes and 1-bromo-2-butene and is ascribed to a chair-like six-membered transition state.Simple reduction od allylic and benzylic halides produces biallyls and bibenzyls, while gem-dibromocyclopropanes afford the corresponding allenes in excellent yields.
THERMISCHE STABILITAET VON BIS(ALK-2-ENYL)ZINK-VERBINDUNGEN
Lehmkuhl, Herbert,Doering, Ingo,Nehl, Hans
, p. 7 - 12 (2007/10/02)
The dialk-2-enylzinc compounds I-III react slowly at 20 to 50 deg C by addition of the Zn-C bond to the C=C bond of an alk-2-enyl group to give oligomers from which the alkenes XIII-XV are released on hydrolysis.For I-III homolytic cleavage of the Zn-Callyl bond, followed by coupling of the allyl radicals to give the alkadienes V-VII, IX and XI predominates above 50 deg C.IV decomposes mainly homolytically even at 20 deg C.
Divalent Lanthanide Derivatives in Organic Synthesis. 1. Mild Preparation of SmI2 and YbI2 and Their Use as Reducing or Coupling Agents
Girard, P.,Namy, J. L.,Kagan, H. B.
, p. 2693 - 2698 (2007/10/02)
The facile synthesis of SmI2 and YbI2 from corresponding metals in THF is described.The reactivity of these potentially powerful reducing agents toward a variety functional groups is tested.Epoxides and sulfoxides are deoxygenated.Aldehydes are selectively reduced in presence of ketones.Alkyl halides or tosylates are converted into alkanes.Only coupling products are obtained from benzylic or allylic halides.In the presence of a SmI2-THF solution, tertiary alcohols are easily obtained from reactions between ketones and alkyl halides.In a similar manner, SmI2 promotes straightforward alkylation of ketones by alkyl sulfonates.Selective addition of polyfunctional halides or tosylates to ketones may be performed.In these reactions, catalytic amounts of FeCl3 enhance the reactivity.
