- Conversion of Carbonyl Compounds to Olefins via Enolate Intermediate
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A general and efficient protocol to synthesize substituted olefins from carbonyl compounds via nickel catalyzed C—O activation of enolates was developed. Besides ketones, aldehydes were also suitable substrates for the presented catalytic system to produce di- or tri- substituted olefins. It is worth noting that this approach exhibited good tolerance to highly reactive tertiary alcohols, which could not survive in other reported routes for converting carbonyl compounds to olefins. This method also showed good regio- and stereo-selectivity for olefin products. Preliminary mechanistic studies indicated that the reaction was accomplished through nickel catalyzed C—O activation of enolates, thus offering helpful contribution to current enol chemistry.
- Cao, Zhi-Chao,Xu, Pei-Lin,Luo, Qin-Yu,Li, Xiao-Lei,Yu, Da-Gang,Fang, Huayi,Shi, Zhang-Jie
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- Thermolysis of Phenyl-substituted 1,2-Dihydronaphthalenes. Evidence for Diphenylbutadienes as Intermediates
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The thermal rearrangement of the four phenyl-substituted 1,2-dihydronaphthalenes (15), (16), (19), and (20) have been studied by flash vacuum pyrolysis (FVP).By using the deuteriated starting compounds -(15) and -(16), it has been established that 1- and 4-phenyl-1,2-dihydronaphthalene (15) and (19) and 2- and 3-phenyl-1,2-dihydronaphthalene (16) and (20) are interconverted via the intermediates 1- and 2-phenyl-2,3-dihydronaphthalene (17) and (18), respectively, through two consecutive, sigmatropic 1,5-hydrogen shifts.In both processes partial oxidation to the corresponding phenylnaphthalenes (21) and (22) takes place.The deuterium distribution in the pyrolysis products suggests that in the hot zone diphenylbutadienes are formed, which are reconverted into phenyldihydronaphthalenes upon reaching the cold receiving flask.By FVP of 4-(p-tolyl)-1,2-dihydronaphthalene (34), 1-phenyl-1-(p-tolyl)butadiene (39), and 1-phenyl-4-(p-tolyl)butadiene (45) the latter type of interconversion could be confirmed.
- Lamberts, Joseph J. M.,Cuppen, Theo J. H. M.,Laarhoven, Wim H.
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p. 1819 - 1828
(2007/10/02)
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