27608-11-3Relevant academic research and scientific papers
Indium/copper-mediated conjugate addition of unactivated alkyl iodides to α,β-unsaturated carbonyl compounds in water
Shen, Zhi-Liang,Cheong, Hao-Lun,Loh, Teck-Peng
supporting information; scheme or table, p. 1051 - 1054 (2009/05/27)
An efficient method for the conjugate addition of unactivated alkyl iodides to α,β-unsaturated carbonyl compounds using indium/copper in water is described. The reactions proceed more efficiently in water than in organic solvents. In, CuI, and InCl3
Photomediated synthesis of β-alkylketones from cycloalkanes
Dondi, Daniele,Cardarelli, Anna Maria,Fagnoni, Maurizio,Albini, Angelo
, p. 5527 - 5535 (2007/10/03)
β-Cycloalkylketones are prepared through a photomediated radical addition reaction onto enones starting from the corresponding alkanes (i.e., cyclopentane, -hexane, -heptane, -dodecane and adamantane). The alkyl radicals are generated via hydrogen abstrac
Regioselective radical ring-opening reaction of bicyclo[4.2.0]octan-2-ones promoted by samarium(II) iodide
Kakiuchi, Kiyomi,Minato, Koichi,Tsutsumi, Ken,Morimoto, Tsumoru,Kurosawa, Hideo
, p. 1963 - 1966 (2007/10/03)
Radical ring-opening reactions of bicyclo[4.2.0]octanones, its C6 alkyl derivatives, and tricyclic ketones promoted by SmI2 gave cyclohexanones via fission of the external cyclobutane bond. The CO2Me, CN, and phenyl derivatives led t
Preparation of 1-phenylcyclohexa-2,5-diene-1-carboxylates and their use in free-radical mediated syntheses
Baguley, Paul A.,Jackson, Leon V.,Walton, John C.
, p. 304 - 309 (2007/10/03)
Synthetic routes to pure 1-phenylcyclohexa-2,5-diene-1-carboxylic acid and derived esters were developed. Esters containing appropriately unsaturated side chains generated the corresponding alkenyl radicals and hence gave good yields of 5-exo ring closure products in organotin-free reactions. Extrusion of phenyl radicals from the intermediate cyclohexadienyl type radicals was not observed, and this alternative β-scission did not compete under any conditions. Yields from alkylations of olefins in analogous intermolecular processes were, however, poor. As a spin-off from the research, it was found that 1-phenylcyclohexa-2,5-diene-1-carboxylic acid (6) was a useful source of hydroxyformyl (formate) radicals in organic solvents.
Reductive free-radical alkylations and cyclisations mediated by 1-alkylcyclohexa-2,5-diene-1-carboxylic acids
Baguley, Paul A.,Walton, John C.
, p. 2073 - 2082 (2007/10/03)
A range of 1-alkylcyclohexa-2,5-diene-1-carboxylic acids were prepared by Birch reduction-alkylation of benzoic acid and their efficiency as mediators of alkyl radical chain addition and cyclisation processes was investigated. Reductive alkylations were respectably successful, even with only one or two equivalents of alkene, for secondary, tertiary and benzylic radicals. Reaction of 1-[2-(cyclohex-2-enyloxy)ethyl]cyclohexa-2,5-diene-1-carboxylic acid yielded the product of exo-trig-cyclisation, i.e. 7-oxabicyclo[4.3.0]nonane, in a yield comparable to that obtained from the tributyltin hydride induced cyclisation of 3-(2′-iodoethoxy)-cyclohexene. This, together with the isolation of both exo- and endo-cyclisation products from 1-[2-(6,6-dimethylbicyclo[3.1.1]hept-2-en-2-ylmethoxy)ethyl]cyclohexa-2,5-diene- 1-carboxylic acid established that ring closures could also be satisfactorily mediated with these reagents. Preparations were completely free of metal contaminants and direct reduction of the alkyl radicals, prior to addition or cyclisation, was completely absent. However, the desired products were accompanied by alkylbenzenes, together with by-products from the initiator decompositions, and this complicated work-up. Failure to obtain 1-[2-(prop-2-yn-1-yloxy)cyclohexyl]cyclohexa-2,5-diene-1-carboxylic acid in Birch reductive alkylations with trans-1-iodo-2-(prop-2-yn-1-yloxy)cyclohexane (and the corresponding bromide) indicated a limitation on precursor synthesis. The Birch reduction-alkylation was not of universal applicability and was suppressed for alkyl halides having β-substituents.
Unique carbon-carbon bond homolysis in 3-alkylcyclohexa-1,4-dienyl-3-carboxylic acid radicals
Baguley, Paul A.,Binmore, Gavin,Milne, Aynsley,Walton, John C.
, p. 2199 - 2200 (2007/10/03)
3-Substituted cyclohexadienyl radicals generated by hydrogen abstraction from 3-alkylcyclohexa-1,4-diene-3-carboxylic acids readily fragment to produce alkyl radicals and benzoic acid; suitably functionalised alkyl groups cyclize in moderate yields.
The Photochemical Cycloaddition Reaction of 2-Cyclohexenone with Alkenes: Trapping of Triplet 1,4-Biradical Intermediates with Hydrogen Selenide
Maradyn, David J.,Weedon, Alan C.
, p. 8107 - 8110 (2007/10/02)
The triplet 1,4-biradical intermediates formed in the photochemical cycloaddition reaction between 2-cyclohexenone and the alkenes cyclopentene and ethoxyethene have been trapped quantitatively with hydrogen selenide.The structures of the biradicals reveal that they are formed by bonding of both the 2-position and the 3-position of the enone to one terminus of the alkene; in the case of ethoxyethene it is exclusively the less substituted terminus of the alkene that becomes bonded to the enone in the biradical intermediates.The yields of the trapped biradicals indicate that the regiochemistry of the photocycloaddition reaction is determined by the manner in which the biradicals partition between fragmentation to give ground state starting materials and closure to give product, and not by their relative rates of formation.The results suggest that the mechanistic factors governing the photocycloaddition chemistry of cyclohexenone are similar to those controlling the photochemistry of cyclopentenones. - Key Words: enone, photochemistry, cycloaddition, alkene, triplet 1,4-biradicals, hydrogen selenide, trapping, regiochemistry.
