RESUMO
Reaction of aryl nitriles with potassium ethyl malonate in the presence of zinc chloride and a catalytic amount of Hünig's base provided beta-amino acrylates in moderate to good yield. Compared to the classical Blaise reaction, this reaction is safer (endothermic), devoid of lacrimatory reagent, and is possible with 0.5-1.0 equiv of zinc chloride.
Assuntos
Acrilatos/síntese química , Nitrilas/química , Acrilatos/química , Catálise , Cloretos/química , Descarboxilação , Malonatos/química , Estrutura Molecular , Potássio/química , Solventes/química , Compostos de Zinco/químicaRESUMO
As part of our studies of metal-catalyzed [m + n (+...o)] cycloadditions, we have previously reported the rhodium-catalyzed [5 + 2] cycloaddition of vinylcyclopropanes (VCPs) and pi-systems. These studies have led to Rh(I) complexes that catalyze these reactions in minutes at room temperature or in water without organic solvents. We describe a comparative evaluation of several chiral catalysts for the [5 + 2] reaction, evaluation of a preferred catalyst, [((R)-BINAP)Rh]+SbF6-, with substrates differing in substitution and tether types-producing enantiomeric excesses >/=95% for several systems. A predictive model for the selectivity is also presented.
Assuntos
Alcenos/química , Catálise , Ciclopropanos/química , Ródio/química , Soluções , Estereoisomerismo , Compostos de VinilaRESUMO
A simple strategy involving thermal decomposition of the methanesulfonyl radical into the methyl radical and the subsequent transfer of an iodine atom or phenyl telluride group was used to develop a tin-free radical acylation reaction (see scheme; V-40=1,1'-azobis(cyclohexane-1-carbonitrile). The key was finding reaction conditions under which the I or PhTe transfer is faster than the direct addition of the alkyl radical to the methanesulfonyl oxime ether.
