139759-73-2Relevant academic research and scientific papers
Mesolytic Cleavage of the O-CO-Bond in Enol Acetate Cation Radicals with Direct Formation of α-Carbonyl Cations. Mechanistic and Synthetic Aspects
Schmittel, Michael,Heinze, Juergen,Trenkle, Holger
, p. 2726 - 2733 (2007/10/02)
For the first time, enol ester cation radicals are reversibly monitored in a cyclic voltammetry experiment.Preparative one-electron oxidation of enol acetates A1-A4 leads to the formation of benzofurans B1-B4 through mesolytic O-CO bond fragmentation to α-carbonyl cations and the acetyl radical.With A3(.+), the kinetics of the O-CO bond cleavage was investigated by cyclic voltammetry, providing ΔH(excit.) = 17.0 kcal mol-1 and ΔS(excit.) = 11 cal mol-1 K-1 in dichloromethane.The slioghtly increased rate of bond dissociation upon adition of acetonitrile is explained with charge localization in the transition state rather than with a solvent-assisted bond cleavage mechanism.The occurrence of curve crossing and isopotential points in the cyclic voltammograms of the model compounds a1-A4 at low scan rates can be rationalized by a multiparameter reaction scheme based on an ECCEDISP mechanism, digital simulation of which confirmed the cleavage selectivety and allowed for the determination of the involved rate constants of the homogeneous chemical reaction steps.
Enol Cation Radicals in Solution. 4. An Improved Synthesis of 4,6,7-Trimethylbenzofurans by Oxidation of β-Mesityl Substituted Enols
Roeck, Maik,Schmittel, Michael
, p. 325 - 329 (2007/10/02)
An improved synthetic access for the construction of 4,6,7-trimethylbenzofurans (B1-B8) through the one-electron oxidation of mesityl-substituted enols (E1-E8) is presented.The transformation can be accomplished in good to excellent yields by using variou
Controlled Oxidation of Enolates to α-Carbonyl Radicals and α-Carbonyl Cations
Roeck, Maik,Schmittel, Michael
, p. 1739 - 1741 (2007/10/02)
Depending on the oxidation strength of the one-electron oxidants either persistent α-carbonyl radicals or α-carbonyl cation derived benzofurans are formed from enolates A1-A6, a result which can readily be rationalized by the measured oxidation potentials
Reaction of Enol Cation Radicals in the Presence of Nucleophiles
Schmittel, Michael,Roeck, Maik
, p. 1611 - 1620 (2007/10/02)
The one-electron oxidation chemistry of three diaryl-substituted enols, 1,1-dimesityl-1-propen-2-ol (7), 1,2-dimesityl-1-propen-1-ol (8), and 2-mesityl-2-phenylethenol (9), has been examined.As a consequence of the pronounced steric shielding around the β
