- Nickel-catalyzed cross-coupling of unactivated alkyl halides and tosylate carrying a functional group with alkyl and phenyl Grignard reagents
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By the use of catalytic amounts of a nickel salt and a 1,3-butadiene, primary and secondary alkyl Grignard reagents undergo cross-coupling with alkyl bromides, iodide, and tosylate carrying a functional group such as amide, ester, and ketone at 0 °C in THF. The present procedure provides a simple, convenient, and practical method for construction of carbon chains in the presence of various functional groups. PhMgBr also gave the corresponding coupling product in a moderate yield.
- Singh, Surya Prakash,Terao, Jun,Kambe, Nobuaki
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scheme or table
p. 5644 - 5646
(2011/02/25)
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- One-carbon homologation of unsymmetrical ketones through magnesium β-oxido carbenoid rearrangement and trapping the enolate intermediates with electrophiles
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A procedure for one-carbon homologation of unsymmetrical ketones, including one-carbon ring-expansion of 2-substituted cyclohexanones, through magnesium β-oxido carbenoid rearrangement as the key reaction is described. Addition of the α-sulfinyl carbanion of 1-chloroethyl p-tolyl sulfoxide to an unsymmetrical ketone gave two diastereomers as adducts in good yields. The adducts were treated with a base to give alkoxides, which were treated with a Grignard reagent to give magnesium β-oxido carbenoids. The β-oxido carbenoid rearrangement then took place to afford one-carbon homologated ketones having a methyl group at the α-position. Remarkable specificity or selectivity was observed in the rearrangement. The magnesium enolate intermediates of this reaction were found to be able to get trapped with several electrophiles to give one-carbon homologated α,α-disubstituted ketones. Origin of the specificity and selectivity is also discussed.
- Tanaka, Shu,Anai, Takehiro,Tadokoro, Makoto,Satoh, Tsuyoshi
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p. 7199 - 7210
(2008/12/20)
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- Novel Acylation of Aliphatic Olefins Promoted by Active Zinc Compounds
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It was found that acylation of a variety of aliphatic olefins with acid chlorides is efficiently promoted by active zinc compounds, which were prepared from a Zn/Cu couple and alkyl iodides.The crude product mixtures were subsequently treated with 1 M KOH in methanol or were subjected to catalytic hydrogenation to afford the corresponding α,β-unsaturated or saturated ketones in good to moderate yields.It was also shown that the reaction fully follows the Markovnikov rule.
- Shono, Tatsuya,Nishiguchi, Ikuzo,Sasaki, Manji,Ikeda, Haruhiko,Kurita, Makoto
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p. 2503 - 2505
(2007/10/02)
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