32199-29-4Relevant academic research and scientific papers
Mechanistic studies of Ce(IV)-mediated oxidation of β-dicarbonyls: Solvent-dependent behavior of radical cation intermediates
Jiao, Jingliang,Zhang, Yang,Devery III, James J.,Xu, Luna,Deng, Jennifer,Flowers II, Robert A.
, p. 5486 - 5492 (2007)
(Chemical Equation Presented) The Ce(IV)-initiated oxidation of synthetically relevant β-diketones and β-keto silyl enol ethers was explored in three solvents: acetonitrile, methylene chloride, and methanol. The studies presented herein show that the rate of reaction between Ce(IV) and the substrates is dependent upon the polarity of the solvent. Thermochemical studies and analysis are interpreted to be consistent with transition state stabilization by solvent being primarily responsible for the rate of substrate oxidation. Kinetic investigation of radical cations obtained from oxidations of β-diketones reveals that a more ordered transition state for the radical cation decay is achieved through the direct involvement of methanol in the deprotonation of the intermediate. In the case of radical cations derived from β-keto silyl enol ethers, experimental data support a mechanism involving unimolecular decay of the intermediate. Remarkably, radical cations derived from β-diketones and β-keto silyl enol ethers are surprisingly stable in methylene chloride.
