85692-23-5Relevant articles and documents
Iridium-catalyzed regiospecific and stereospecific allylic amination for the syntheses of α,β-unsaturated γ-amino esters and the bifurcation of the reaction pathway leading to the formation of oxazolidin-2-ones
Lee, Jun Hee,Lee, Sang-Gi
, p. 2922 - 2927 (2013/07/19)
A pair of iridium-catalyzed regiospecific and stereospecific reactions of the carbonates of γ-hydroxy α,β-unsaturated esters were developed. The reaction pathways are strongly affected by the choice of amines employed. A diverse range of γ-substituted α,β-unsaturated γ-amino esters were prepared in excellent yields with various amine nucleophiles such as benzylamine, diallylamine, morpholine, aniline and N-methylaniline. Substitution at the γ-position was well tolerated, encompassing alkyl, aryl and heteroaryl substituents. Enantioenriched (E)-α,β-unsaturated γ-amino esters could also be synthesized from the corresponding enantioenriched allylic carbonates with complete chirality transfer. In sharp contrast, a series of 3,4-disubstituted oxazolidin-2-ones were obtained by using allylamine as a nucleophile.
Kinetics of Nucleophilic Substitution Reaction of Ethyl 4-Bromocrotonate with Anilines in Aqueous Acetone
Shunmugasundaram, A.,Radhakrishnan, K.
, p. 827 - 830 (2007/10/02)
The second order rate constants for the reaction of ethyl 4-bromocrotonate with aniline and p- and o-substituted anilines and α- and β-naphthylamines have been evaluated in 90percent acetone-10percent water (v/v) mixture at 30 deg C, 35 deg C and 40 deg C.In the reaction of p-substituted anilines, the electron-releasing groups facilitate the reaction while electron-withdrawing groups retard it.The ρ-value is calculated to be -1.819+/-0.109 (s=0.039; r=0.998) at 35 deg C by correlation analysis of log k2 with the Hammett ?/?- constants. β-Naphthylamine reacts at a faster rate than α-naphthylamine.The Broensted plot of log k2 versus pKa is fairly linear with βN = 0.640+/- 0.175 (r=0.954; s=0.175) at 35 deg C indicating that there is extensive bond formation between aniline and the reaction centre in the transition state.In the reaction of o-substituted anilines, the results of analysis of the rate data in terms of extended Hammett equation: log k=α?I+β?R+h, show that both localized and delocalized effects are important.The coefficients of ?I and ΣR are all negative indicating that electron-releasing groups accelerate and electron-withdrawing groups retard the rate of reaction.
