- Sterically Hindered Double-Bond Systems, VII. On the Reaction of Succinic Esters with tert-Butyllithium
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Addition of tert-butyllithium to dimethyl (1a) and diethyl succinate (1b), respectively, provides 2,2,7,7-tetramethyl-3,6-octanedione (3) in good yield as well as the ketoesters 5a/b and the cylized products 6 and 7.The model of formation of these latter side products is discussed, and several published errors concerning these transformations are corrected. - Key Words: Ketones, sterically hindered / Lactones, gem-di-tert-butylated / tert-Butyllithium, reaction with dialkyl dicarboxylates
- Hopf, Henning,Haenel, Ralf
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p. 2347 - 2348
(2007/10/02)
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- NEW SYNTHESIS OF γ-DIKETONES
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A new method of synthesizing γ-diketones by the reactions of bis(triethylsilyl)- or bis(triethylgermyl)-mercury with α-bromo ketones was developed.The reaction proceeds by a radical mechanism with the intermediate formation of silyl or germyl enol ethers.
- Gendin, D. V.,Petrov, P. A.,Mokov, A. S.,Voronkov, M. G.
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p. 1724 - 1727
(2007/10/02)
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- Oxovanadium-Induced Oxidative Desilylation for the Selective Synthesis of 1,4-Diketones
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Silyl enol ethers underwent the VO(OR)Cl2-induced homo- or cross-coupling giving 1,4-diketones selectively via one-electron oxidative desilylation.
- Fujii Takashi,Hirao, Toshikazu,Ohshiro, Yoshiki
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p. 5823 - 5826
(2007/10/02)
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- Direct and Regiocontrolled Synthesis of α-Phenyl Ketones from Silyl Enol Ethers and Diphenyliodonium Fluoride
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The efficiacy of diphenyliodonium fluoride (1, DIF) for the phenylation of silyl enol ethers was investigated.When the silyl enol ethers of cyclopentanone, 2-methylcyclopentanone, cyclohexanone, 2-methylcyclohexanone, acetophenone, 2-pentanone, diisopropyl ketone, and pinacolone were mixed with DIF in tetrahydrofuran, either α-phenyl or α,α-diphenyl ketones were produced and isolated in yields ranging from 20 to 88percent.That the regiochemistry of α-phenylation can be controlled by an appropriate choice of silyl enol ether was demonstrated with the kinetic and thermodynamic silyl enol ethers of 2-methylcyclohexanone, the thermodynamic silyl enol ether of 2-methylcyclopentanone, and the kinetic silyl enol ether of 2-pentanone. 3,3-Dimethyl-2-(silyloxy)-1-butene gave a dehydro dimer of pinacolone with DIF in addition to α-phenylpinacolone, thus suggesting that phenylations of silyl enol ethers with DIF may proceed via radical intermediates.
- Chen, Kuanchiang,Koser, Gerald F.
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p. 5764 - 5767
(2007/10/02)
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- THE REACTION OF CARBANIONS WITH 2-SUBSTITUTED -2-NITROPROPANES SUBSTITUTION AND DIMERIZATION OCCURRING BY RADICAL CHAIN PROCESSES INVOLVING ELECTRON TRANSFER
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The reaction of mono-enolate anions with O2NCMe2X where X=Cl, NO2, p-MePhSO2 yield coupling (RCOCH(R')(CMe2NO2) and enolate dimerization products (RCOCH(R')CH(R')COR) by free radical chain mechanisms involving bimolecular substitution or electron transfer reactions between the enolate anion and the intermediate nitro alkane radical anion (XCMe2NO2(1-)).
- Russell, Glen A.,Mudryk, Boguslaw,Ros, Francisco,Jawdosiuk, Mikolaj
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p. 1059 - 1068
(2007/10/02)
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