- A ruthenium-based catalytic system with switchable selectivity between cyclotrimerization and enyne metathesis/Diels-Alder reactions of terminal alkynes
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In this study, we report a practical catalytic system, [RuCl 2(p-cymene)]2/IPr (IPr: 1,3-bis(2,6 diisopropylphenyl) imidazol-2-ylidene), that can switch between cyclotrimerization and cross enyne metathesis. The cyclotrimerization reaction of phenylacetylene catalyzed by [RuCl2(p-cymene)]2 can be switched to enyne metathesis by the introduction of a sterically hindered N-heterocyclic carbene. The 1,3-diene formed during this reaction reacts with dienophiles to form the Diels-Alder adduct. A practical one-pot synthesis method, utilizing enyne metathesis/Diels-Alder reactions, was used to construct cyclic compounds in an efficient manner.
- Karabulut, Solmaz,Sariaslan, Begüm,?ztürk, Bengi ?zgün
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- Silicon-Directed Diene Synthesis
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A synthesis of 2-substituted-1,3-dienes is reported which uses silicon as a control element: eight aldehydes were converted into α-silyl ketones by treatment with trimethylsilylmethylmagnesium chloride and rapid Collins oxidation.Addition of vinylmagnesiu
- Brown, Paul A.,Bonnert, Roger V.,Jenkins, Paul R.,Lawrence, Nicholas J.,Selim, Mohammed R.
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p. 1893 - 1900
(2007/10/02)
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- A SILICON DIRECTED DIENE SYNTHESIS
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A convenient method for the conversion of a series of aldehydes into substituted dienes is reported which uses silicon as a control element.
- Brown, Paul A.,Bonnert, Roger V.,Jenkins, Paul R.,Selim, Mohammed R.
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p. 693 - 696
(2007/10/02)
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- Reaktivity of Substituted 1,3-Butadienes in Diels-Alder-Reactions
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Kinetic data for the reaction of substituted 1,3-dienes with tetracyanoethylene (TCNE) and other dienophiles are interpreted in terms of the FMO-model.While the expectations are fulfilled qualitatively, the kinetic data cannot be correlated quantitatively.This shows that in Diels-Alder reactions besides HOMO-LUMO separation other factors play an important role, for instance the 1,4-distance in the diene and the conformational equilibrium cisoid transoid of the diene.The kinetic data are in accord with a one-step mechanism of the cycloaddition reaction.
- Ruecker, Christa,Lang, Dietrich,Sauer, Juergen,Friege, Henning,Sustmann, Reiner
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p. 1663 - 1690
(2007/10/02)
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