55674-18-5Relevant academic research and scientific papers
Synthesis of cyclobutenes by highly selective transition-metal-catalyzed ring expansion of cyclopropanes
Xu, Huadong,Zhang, Wen,Shu, Dongxu,Werness, Jenny B.,Tang, Weiping
supporting information; experimental part, p. 8933 - 8936 (2009/05/30)
(Chemical Equation Presented) A highly chemoselective, regioselective, and stereospecific synthesis of polysubstituted cyclobutenes, by catalyst-controlled ring expansion of cyclopropanes via metal carbene intermediates, is reported. Transition-metal cata
Catalytic Decomposition of Ethyl Diazopyruvate in the Presence of Electron-Deficient and Hydrocarbon Alkenes. Cyclopropanation vs. Carbon-Hydrogen Insertion
Alonso, Miguel E.,Jano S., Patricia,Hernandez, Maria I.
, p. 5299 - 5302 (2007/10/02)
The bis(copper acetylacetonate)-catalyzed decomposition of ethyl diazopyruvate (EDP, 1) in the presence of electron deficient and hydrocarbon alkenes has been examined.The steric and electronic factors governing the reaction were evaluated.While mono- and disubstituted hydrocarbon alkenes such as cyclohexene, 4-(tert-butylmethylene)cyclohexane, styrene, and indene furnished the corresponding ethoxalylcyclopropane derivatives in moderate to satisfactory yields, polysubstituted alkenes such as 1-methylcyclohexene and 1,2-dimethylcyclohexene did not give separable adducts.Electron-withdrawing substituents (Cl, Br, NO2) directly bond to the substrate olefin and substitution of two phenyl groups in conjugation with the alkene precluded the formation of adducts.Only α-chloro- and p-chlorostyrene were found reactive toward the EDP-derived copper carbenoid.No C-H insertion products were detected in any case.It is shown that products of apparent allylic C-H insertion are actually the consequence of a 1,5 hydrogen shift of the initially formed cyclopropane.The evidence collected suggests that the EDP copper carbenoid is slightly less electrophilic than the copper carbenoid derived from ethyl diazoacetate.
