- Sulphone-mediated cyclobutanone to α-alkoxy-cyclopentanone ring expansion reactions; scope, limitations and applications
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The bicycloalkanones (1)-(3) were treated with the lithiated sulphone (4) to give the ring expanded α-methoxyketones (12), (14) and (16) generally as a mixture of epimers. The same bicycloalkanones furnished the α-benzyloxyketones (13), (15), and (17) on reaction with reagent (5). The ketone (3) reacted with the sulphone anion (6) to give, after Lewis acid treatment, the α-allyloxycyclopentanone derivatives (27a) and (27b) and one of these compounds (27b) was transformed into the ether (31). The bicycloheptanone (20) was converted into four ring-expanded products (22a), (22b), (24a) and (24b) and one of the compounds (24a) was used to synthesise the prostacyclin analogue (36). A brief study was made of the mechanism of the Lewis-acid catalysed rearrangement of the intermediate hydroxy sulphone to the ring-expanded compounds.
- Finch, Harry,Mjalli, Adnan M. M.,Montana, John G.,Roberts, Stanley M.,Taylor, Richard J. K.
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p. 4925 - 4950
(2007/10/02)
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- Anodic Oxidation of (Trimethylsilyl)methanes with ?-Electron Substituents in the Presence of Nucleophiles
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It was found that oxidation potentials of methanes with ?-electron substituents were decreased by introduction of a trimethylsilyl group.The anodic oxidation of benzyl-, allyl-, aryl(or alkyl)thiomethyl-, and aryloxymethyl-substituted trimethylsilanes smoothly proceeded in the presence of nucleophiles, e.g. alcohols and carboxylic acids, to eliminate the trimethylsilyl groups giving the corresponding alkoxylated and carboxylated products in moderate or high yields without full optimization of electrolytic conditions, while aminomethylsilanes did not undergo such a kind of anodic oxidation.
- Koizumi, Toshio,Fuchigami, Toshio,Nonaka, Tsutomu
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p. 219 - 225
(2007/10/02)
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- A Novel Synthesis of Phenylthiomethyl (PTM) Ethers and Esters by Anodic Oxidation of Phenyl Trimethylsilylmethyl Sulfide
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It was found that anodic oxidation of phenyl trimethylsilylmethyl sulfide in the presence of alcohols and carboxylic acids afforded various kinds of PTM ethers and esters, respectively, in good to reasonable yields.
- Koizumi, Toshio,Fuchigami, Toshio,Nonaka, Tsutomu
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p. 1095 - 1096
(2007/10/02)
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