- A new synthesis of allyl sulfoxides via nucleophilic addition of sulfinyl carbanions to group 6 fischer carbene complexes
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(Chemical Equation Presented) A novel synthesis of allyl sulfoxides has been developed. Primary α-lithiosulfinyl carbanions react with group 6 Fischer carbene complexes to give allyl sulfoxides as products. The Fischer carbene complex experiments involve a 1,2-addition of two molecules of sulfinyl carbanion to give an intermediate that, after a β-elimination, furnishes the mentioned product.
- Barluenga, Jose,Fananas-Mastral, Martin,Aznar, Fernando
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- Heck reactions of 2-substituted enol ethers with aryl bromides catalysed by a tetraphosphine/palladium complex
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cis,cis,cis-1,2,3,4-Tetrakis(diphenylphosphinomethyl)cyclopentane/ [PdCl(C3H5)]2 efficiently catalyses the Heck reaction of β-substituted enol ethers with aryl bromides. Employing β-methoxystyrene, 3-ethoxyacrylonitrile or methyl 3-methoxyacrylate, the regioselective α-arylation of these enol ethers was observed in all cases, and mixtures of Z and E isomers were generally obtained, which in many cases yielded a single ketone product after acid treatment. The stereoselectivity of this reaction depends on steric and electronic factors, and better stereoselectivities in favour of Z isomers were observed with electron-rich or sterically congested aryl bromides. Better yields were obtained for this reaction with electron-rich or sterically congested aryl bromides than with electron-poor aryl bromides. This observation suggests that with these β-substituted enol ethers the rate-limiting step of the catalytic cycle is not the oxidative addition of the aryl bromide to the palladium complex.
- Battace, Ahmed,Zair, Touriya,Doucet, Henri,Santelli, Maurice
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p. 459 - 462
(2007/10/03)
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