Michael Additions versus Cycloaddition Condensations with Ethyl Nitroacetate and Electron-Deficient Olefins
作者:Elena Trogu、Francesco De Sarlo、Fabrizio Machetti
DOI:10.1002/chem.200802652
日期:2009.8.10
nitroacetate (1) reacts with electron‐poor olefins in the presence of a base to give either the Michael adducts 3 or the isoxazoline cycloadducts 4, resulting from water elimination. The proportions of the two products depend on the reaction conditions and change in the course of the process. Kinetic profiles for the two reactions show that the cycloaddition‐condensations require long induction times that dramatically
Conjugate Addition versus Cycloaddition/Condensation of Nitro Compounds in Water: Selectivity, Acid-Base Catalysis, and Induction Period
作者:Luca Guideri、Francesco De Sarlo、Fabrizio Machetti
DOI:10.1002/chem.201202698
日期:2013.1.7
react in water as in chloroform with electron‐deficient dipolarophiles to give condensation or conjugate addition products under basecatalysis. In general, high selectivity towards condensation is observed in water, with shorter induction periods than in chloroform. In water, condensations slowly occur even without base; kinetic profiles evidence the catalytic effect of the base, which should be related