- Cyclisation de composes acetyliniques carbonyles via leur ether d'enol silyle: II. Synthese et reactivite de quelques ethers d'enols derivees d'aldehydes ou de cetones acetyleniques terminaux
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A number of silyl enol ethers of ω-acetylenic ketones or aldehydes have been prepared following various literature procedures which are compared to each other.By treatment with mercury (II) chloride (1.1 equiv.) in the presence of HMDS (0.2 or 1.5 equiv.) at room temperature, followed by acidification with aqueous HCl-NaI, silyl enol ethers 1, 2, 3, 9, 11, 12 and 13 are cyclized in high yield into 2-alkylidene-1-oxocyclopentanes, methylene- spiro or poly-cyclanones, a methylene cyclopentane unit being formed in the reaction.In the same way, from silyl enol ethers 4, 8 and 10 a methylenecyclohexane unit is formed.In all the products the exocyclic position of the C=C double bond so formed is fully maintained.
- Boaventura, Maria-Amelia,Drouin, Jacques
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p. 1015 - 1026
(2007/10/02)
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- Reactions of 3-Hydroxyvinyl Selenones with Alkoxides. Oxetane Formation and Fragmentation Reactions
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3-Hydroxyvinyl phenyl selenones are prepared and their behavior as conjugate addition acceptors has been investigated.As a result, a selenonyl group has been found to activate the C=C bond for conjugate addition of nucleophiles and further to behave as an
- Shimizu, Makoto,Ando, Ryoichi,Kuwajima, Isao
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p. 1230 - 1238
(2007/10/02)
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