21504-43-8Relevant articles and documents
Structural determination, DFT Calculation, and Formation Mechanism of Ethyl 2-Cyano-3-Alkoxypent-2-enoates synthesized via Ru-mediated coupling reaction between α,β-unsaturated acetals and cyanoacetate
Seino, Hidetake,Kondo, Takumi,Mochizuki, Chihiro,Tokunaga, Ken,Yamaguchi, Motowo,Sato, Mitsunobu
, p. 79 - 87 (2017/08/14)
Ethyl 2-cyano-3-Alkoxypent-2-enoates were synthesized in moderate yields via the coupling reaction between α,β- unsaturated acetals and cyanoacetate, catalyzed by [RuHCl- (CO)(PPh3)3]. The E-And Z-isomers were separated and determined by X-ray crystallography for the first time. Structural distortion associated with steric hindrance around the tetrasubstituted alkene moiety was revealed: e.g., the C(carbonyl)C( α)C( β) angle expands to about 125°. Density functional theory calculation was performed, and the restricted B3LYP hybrid functional with the 6-31G(d,p) basis set was found to successfully elucidate the solid-state structure and conformation, as well as spectroscopic properties. A plausible formation mechanism was proposed, in which the Ru complex catalyzed the C=C bond migration of the α,β-unsaturated acetal to give the corresponding ketene acetal and assisted the subsequent condensation reaction with cyanoacetate to some extent.
2-Ethoxyvinyllithiums and diethoxyvinyllithiums: What makes them stable or fragile?
Schlosser, Manfred,Wei, Heng-Xu
, p. 1735 - 1742 (2007/10/03)
The elusive (E)-2-ethoxyvinyllithium can be readily generated in tetrahydrofuran at -75 °C from (E)-1-bromo-2-ethoxyethylene by halogen/metal exchange and subsequently trapped with electrophiles. Alkylation opens a convenient entry to (E)-configurated enethers. (E)-2-Ethoxyvinyllithium decomposes rapidly at -50 °C whereas its (Z)-isomer, which lacks the possibility to eliminate lithium ethoxide in a favorable anti-periplanar process, is stable under the same conditions. (E)-1,2-Diethoxyvinyllithium even sustains reflux temperatures (approximately 75 °C). 2,2-Diethoxyvinyllithium and (Z)-1,2-diethoxyvinyllithium can be conserved at 0 °C although this time loss of alcoholate can occur in the anti-mode. Obviously it matters whether the energy-rich ethoxyacetylene is formed as the elimination product or simple acetylene, as in the case of (E)-2-ethoxyvinyllithium.
2,2-Di(ethoxy)vinyllithium: A synthetic equivalent of the ethyl acetate anion
Wei,Schlosser
, p. 2771 - 2772 (2007/10/03)
2,2-Diethoxyvinyllithium can be readily generated from 2-bromo-1,1,-diethoxyethylene by treatment with butyllithium. When dissolved in tetrahydrofuran, it can be stored at -25°C for hours, but decomposes rapidly at 0°C.