The reaction of bis(acetonitrile)bis(diethyl fumarate)cobalt(0) with dibromomethane gave diethyl trans-1,2-cyclopropanedicarboxylate in a 67% yield based on the cobalt complex. Dimethyl cis-1,2-cyclopropanedicarboxylate was obtained in a 52% yield from the reaction of dimethylmaleate with dibromomethane in the presence of acetonitrilebis(dimethylmaleate)nickel(0) accompanied by the formation of the
Reactions of stabilized sulfur ylides with α,β-unsaturated alkoxychromiumcarbene complexes
作者:Benito Alcaide、Luis Casarrubios、Gema Domínguez、Angel Retamosa、Miguel A. Sierra
DOI:10.1016/0040-4020(96)00796-x
日期:1996.10
stable ylides would add preferentially to the carbene carbon, 1,4-addition increasing as the stability of the ylide does. For more stable ylides 1,4-addition is preferred and substitution at the β-carbon has little effect in the chemoselectivity. Methoxycarbonylmethylentriphenylphosphorane exclusively add to the carbene carbon while ethyl diazoacetate is unreactive towards α,β-unsaturated alkoxychromium-carbene
Cyclopropane Formation by Copper-Catalysed Indirect Electroreductive Coupling of Activated Olefins and Activated α,α,α-Trichloro or Gem-Dichloro Compounds
作者:S. Sengmany、E. Léonel、J. P. Paugam、J.-Y. Nédélec
DOI:10.1055/s-2002-20969
日期:——
electroreductive coupling ol activatedolefins and activated α,α,α-trichloro or gem-dichloro compounds (Cl 3 CCO 2 Me, PhCCl 3 . Ph 2 CCl 2 , PhCHCl 2 ). This process,using a copper complex in catalytic amountss is convenient for the reagent couple activatedolefin/ activated polyhalide, whatever the reduction potential of each reagent relative to each other. The main advantage of our electrochemical process
Cyclopropane formation by nickel-catalysed electroreductive coupling of activated olefins and unactivated gem-dibromo compounds
作者:Stéphane Sengmany、Eric Léonel、Jean Paul Paugam、Jean-Yves Nédélec
DOI:10.1016/s0040-4020(01)01133-4
日期:2002.1
Cyclopropylderivatives have been prepared with good yields by transition-metal catalysed electroreductive coupling of activatedolefins and unactivated gem-dibromo compounds. This electrolysis is characterized by the use of a Fe/Ni catalyst system, acetonitrile as the solvent and a catalytic amount of triphenylphosphine as ligand. This procedure is a good alternative to the classical preparations
Cyclopropane formation by electroreductive coupling of activated olefins and gem-polyhalo compounds
作者:Eric Léonel、Jean Paul Paugam、Sylvie Condon-Gueugnot、Jean-Yves Nédélec
DOI:10.1016/s0040-4020(98)00059-3
日期:1998.3
be involved to lead to the products. The radical anion of the olefin can react with the halo compound by electron-tranfer followed by radical coupling, or be reduced into the dianion which reacts by nucleophilicdisplacement.