- Base-Induced Cyclization of α-Chloro- β,γ-Unsatured Ketones. Facile Synthesis of Tri- and Tetrasubstituted 2-Cyclopenten-1-ones
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Base-induced cyclization of fully substituted α-chloro β,γ-unsatured ketones results in substituted cyclopentenones.Potassium tert-butoxyde, lithium diisopropylamide, sodium hydroxide, and ammonium hydroxide can be used as the base for this process.In the case of ammonium hydroxide , it is proposed that initial formation of an enamine is followed by an intramolecular SN2'reaction of the enamine carbon.For all other bases, the reaction most likely proceeds through a ketone enolate.Application of this novel cyclization has been extended to the synthesis of several 2,3-substituted, 2,3,5-trisubstituted, and 2,3,5,5-tetrasubstituted 2-cyclopenten-1-ones.
- Mathew, Jacob
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p. 713 - 716
(2007/10/02)
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- Synthesis of 2,3,5-trisubstituted-2-cyclopentenones via base induced cyclization of alpha-chloro unsaturated ketones
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2,3,5-trisubstituted-2-cyclopentenones or 2,3-disubstituted-2-cyclopentenones (such as cis-jasmone) are prepared by contacting a 3-chloro-3,4-disubstituted-4-pentene-2-one with a strong base. Methods of preparing the reactants are also disclosed.
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- SYNTHETIC APPLICATIONS OF 2-PHENYLSELENENYLENONES-III AN OVERVIEW
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2-Phenylselenenylenones are versatile species which can be selectively converted a number of different ketones and enones in high overall yields.
- Liotta, Dennis,Saindane, Manohar,Barnum, Christopher,Zima, George
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p. 4881 - 4890
(2007/10/02)
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- A NEW ROUTE TO 1,4-DIKETONES AND ITS APPLICATION TO (Z)-JASMONE AND DIHYDROJASMONE SYNTHESIS.
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(Z)-Jasmone, dihydrojasmone and other 3-methylcyclopent-2-en-1-ones are easily synthetized starting from aldehydes and 1-(2-methyl-1,3-dioxolane-2-yl)-2-nitroethane as reagent for 3-ketobutyl anion synthon.Nitro-aldol condensation is the chainleghtening reaction followed by oxidation and denitration via p-toluenesulfonylhydrazones of the corresponding α-nitroketones.Removal of protecting groups gives 1,4-diketones which are then cyclized with alkali.
- Rosini, Goffredo,Ballini, Roberto,Sorrenti, Pietro
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p. 4127 - 4132
(2007/10/02)
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- Synthetic Applications of 2-Phenylselenenyl Enones. Selective Formation of Exocyclic or Endocyclic Enones from a Common Intermediate
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2-Phenylselenenyl enones are versatile species which can be selectively converted into a number of different ketones and enones (e.g.5, 6, 9, 10, or 11) in high overall yields.
- Zima, George,Barnum, Christopher,Liotta, Dennis
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p. 2736 - 2737
(2007/10/02)
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