- gem-Dimethylcyclopropanation using triisopropylsulfoxonium tetrafluoroborate: Scope and limitations
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A new nucleophilic isopropyl transfer reagent, triisopropylsulfoxonium tetrafluoroborate, has been prepared and evaluated. Thus, using this reagent and NaH in DMF, a range of electron deficient alkenes, including several chalcone analogues, α,β-unsaturated ketones, dienones and quinones, plus α,β-unsaturated esters, nitrile, sulfone and nitro examples, have been converted into the corresponding gem-dimethylcyclopropane compounds.
- Edwards, Michael G.,Paxton, Richard J.,Pugh, David S.,Whitwood, Adrian C.,Taylor, Richard J. K.
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- An improved gem-dimethylcyclopropanation procedure using triisopropyl-sulfoxonium tetrafluoroborate
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A new procedure for the cyclopropanation of α,β-unsaturated carbonyl compounds and related systems is described which employs triisopropylsulfoxonium tetrafluoroborate and sodium hydride in dimethylformamide. Using this reagent, a range of α,β-unsaturated ketones (and an ester and a vinyl nitro example) has been converted into the corresponding gem-dimethylcyclopropyl carbonyl compounds; in addition, a preliminary result is described in which an activated alcohol is converted directly into a gem-dimethylcyclopropyl ketone by a one-pot tandem oxidation-cyclopropanation sequence, albeit in low yield. Georg Thieme Verlag Stuttgart.
- Edwards, Michael G.,Paxton, Richard J.,Pugh, David S.,Taylor, Richard J. K.
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p. 521 - 524
(2008/12/21)
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- The effects of triplet sensitizers' energies on the photoreactivity of β,γ-unsaturated methyl ketones
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(Chemical Equation Presented) Triplet determines reactivity: β,γ-Unsaturated ketones 1 do not undergo the oxa-di-π-methane (ODPM) rearrangement in the presence of acetophenone or 3-methoxyacetophenone as a triplet sensitizer. However, they afford the ODPM
- Armesto, Diego,Ortiz, Maria J.,Agarrabeitia, Antonia R.,El-Boulifi, Noureddin
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p. 7739 - 7741
(2007/10/03)
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- Novel oxa-di-π-methane and Norrish type I reactions in the S2 (π,π*) excited state of a series of β,γ-unsaturated ketones
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(Chemical Equation Presented) β,γ-Unsaturated methyl ketones with electron-withdrawing groups at the γ-position of the ene moiety undergo ODPM rearrangements and Norrish type I reactions on direct irradiation at 254 nm. The results are consistent with the
- Armesto, Diego,Ortiz, Maria J.,Agarrabeitia, Antonia R.,Martin-Fontecha, Mar
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p. 2687 - 2690
(2007/10/03)
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- A novel route to cyclopropyl ketones, aldehydes, and carboxylic acids
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Cyclopropanation of α,β-unsaturated N-methoxy-N-methyl amides provided the cyclopropyl amides in far superior yields to those obtained with the corresponding ketones. The desired ketones are then readily accessible by the addition of organometallic reagents. Access to a variety functional groups, including aldehydes and carboxylic acids, is also described.
- Rodriques, Karen E.
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p. 1275 - 1278
(2007/10/02)
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