109277-85-2Relevant academic research and scientific papers
The Effect of an Electron-donating β-Substituent on the Configurational Stability and Reactivity of Vinyl Carbanions
Feit, Ben-Ami,Haag, Brigitte,Kast, Juergen,Schmidt, Richard R.
, p. 2027 - 2036 (2007/10/02)
The effect of an electron donating β-substituent A (A = N(CH2)2O(CH2)2, NCH2CH2CH2CH2, OMe, SMe, or OPh) on the relative configurational stabilities and nucleophilic reactivities of the dimethyl esters of α-lithiated fumaric acid (17)-Li and maleic acid (18)-Li was studied in THF, by comparing their reaction products with electrophiles (MeOH, Ph2CO, aldehydes).It was confirmed that when located at a trans position to the vinyl carbanion, the substituent A had two inter-related effects: decreasing the configurational stability of the vinyl carbanion and increasing its nucleophilic reactivity.The rapidly-established (17)-Li (18)-Li equilibrium was completely on the (18)-Li side with A = OR, SR, NR2.The products formed were those derived from (18)-Li only (with MeOH) or from both (17)-Li and (18)-Li depending on both the relative nucleophilic reactivities of the intermediates and on the electrophilicity of the electrophile.The products derived from (18)-Li predominated with the more reactive electrophiles.
