- Functional Group Hybrids. Reactivity of α'-Nucleofuge α,β-Unsaturated Ketones. 1. Reactions with Organocopper Reagents
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A series of α-nucleofuge α',β'-unsaturated ketones encompassing a variety of structural types and nucleofuges was prepared.Treatment of these compounds with lithium dimethylcuprate or methylcopper leads primarily to either reductive cleavage of the α-nucl
- Barbee, Thomas R.,Albizati, Kim F.
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p. 6764 - 6773
(2007/10/02)
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- PHOTOOXYGENATION OF TETRAMETHYLALLENE COMPETING (2+2) CYCLOADDITION AND ENE-REACTIONS WITH SINGLET OXYGEN
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TPP-sensitized photooxygenation of tetramethylallene (4) in carbon tetrachloride yields acetone (5), 2,4-dimethyl-4-hydroxy-1-penten-3-one (8) and 2,4-dimethyl-1,4-pentadien-3-one (9) in a ratio of 35:20:45, besides minor amounts of resinous products and carbon dioxide.Isomerization of 4 to 2,4-dimethyl-1,3-pentadiene (6) does not occur under the reaction conditions.DABCO quenches the photooxygenation, whereas 2,4,6-tri-t-butylphenol (10) enhances the oxygen consumption rate but leaves the ratio of 5:8:9 unchanged.These results indicate that 4 is oxygenated by singlet oxygen.A mechanism is proposed according to which acetone is generated via a (2+2) cycloaddition whereas 8 and 9 are formed via an ene-reaction between 4 and singlet oxygen.
- Gollnick, Klaus,Schnatterer, Albert
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p. 5029 - 5032
(2007/10/02)
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