- Experimental and semiemprical studies of chemical reactivity of dialkylcadmium reagents addition to α,β-enones
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Experimental and semiempirical calculations were carried out to study the reactivity of dialkylcadmium reagents addition to α,β-enones. It was demonstrated that α,β-enone such as benzoquinone with low lying LUMO energy reacts via single electron transfer (SET) mechanism with the formation of the 1,2 or 1,4-type alkyl addition product depending on the reaction temperature and substrate structure. Site and chemoselectivity in unsymmetrical benzoquinone derivatives are determined by the stability of the cadmium coordinated semienone complex intermediates and the carbon spin densities of these reactive species respectively. On the other hand, by increasing the LUMO energy of α,β-enone system, the reaction mechanism changes from SET to polar addition affording the 1,4-type alkyl addition product. The establishment of a correlation scale between substrate LUMO energies and reaction mechanism presented in this article will be discussed.
- Ghandi, Mehdi,Shahidzadeh, Mansour
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p. 4918 - 4925
(2007/10/03)
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- Evidence for single electron transfer (SET) pathway in the reaction of primary alkylcadmium reagents with p-benzoquinone
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The reaction of primary alkylcadmium reagents with p-benzoquinone at various conditions was studied. On the basis of our results, reaction proceeds through a SET mechanism that forms loose and tight intermediates, which produce quinole (1) and substituted hydroquinone (2). In both cases, hydroquinone (3) is obtained in different yields.
- Shahidzadeh, Mansour,Ghandi, Mehdi
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p. 108 - 111
(2007/10/03)
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- Quinone Alkylation Using Organocadmium Reagents: A General Synthesis of Quinols
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Reactions of p-benzoquinone with organocadmium reagents yield quinols, the result of quinone carbonyl monoalkylation. The reactions proceed in good yield and are devoid of bisaddition and hydroquinone byproducts. Quinone alkylations using this method show
- Aponick, Aaron,McKinley, Jason D.,Raber, Jeffrey C.,Wigal, Carl T.
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p. 2676 - 2678
(2007/10/03)
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- The Addition of Organolithium Reagents to Quinone Silyl Methyl Monoketals. A Useful Expedient in the Synthesis of p-Quinols Having Acid-Sensitive Groups
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Acid hydrolyses of dimethyl ketals 4-alkyl- and 4-aryl-4-hydroxy-2,5-cyclohexadienones having an acid-sensitive functionality often afford low or no yields of the respective 4-substituted 4-hydroxy-2,5-cyclohexadienones (p-quinols).However, addition of me
- Stern, Alan J.,Swenton, John S.
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p. 2465 - 2468
(2007/10/02)
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- REACTIONS OF ORGANOLITHIUM REAGENTS WITH p-BENZOQUINONES AND CYCLOHEXADIENONS, SYNTHESIS OF 4-ALKYL-4-HYDROXYCYCLOHEXA-2,5-DIEN-1-ONES AND 1,4-DIALKYLCYCLOHEXA-2,5-DIENE-1,4-DIOLS.
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Addition of organolithium reagents to p-benzoquinones in ether gives the corresponding 4-alkyl-4-hydroxycyclohexa-2,5-dien-1-ones.Addition of excess of the reagent to the p-benzoquinones, or to the 4-alkyl-4-hydroxycyclohexa-3,5-dien-1-ones, in tetrahydrofuran, gives the corresponding dialkylcyclohexa-2,5-diene-1,4-diols.
- Fischer, A.,Henderson, N.
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p. 701 - 704
(2007/10/02)
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