412017-63-1Relevant academic research and scientific papers
Unusual tandem oxidative C-C bond cleavage and acetalization of chalcone epoxides in the presence of iodine in methanol
Jadhav, Balaso G.,Samant, Shriniwas D.
supporting information, p. 1591 - 1595 (2014/07/08)
An unusual reaction of chalcone epoxides is observed where chalcone epoxides on heating with iodine in methanol leads to α,α- dimethoxyacetophenones, through C-C bond cleavage followed by acetalization of the formyl group. The process occurs through ring
Hydrazine sulphate: a cheap and efficient catalyst for the regioselective ring-opening of epoxides. A metal-free procedure for the preparation of β-alkoxy alcohols
Leit?o, Alcino J.L.,Salvador, Jorge A.R.,Pinto, Rui M.A.,Sá e Melo, M. Luísa
, p. 1694 - 1697 (2008/09/19)
An efficient and general procedure for the regioselective ring opening of epoxides with alcohols to afford the corresponding β-alkoxy alcohols, using hydrazine sulphate as catalyst, is described. This new metal-free process was found to be highly versatile allowing the use of primary, secondary and tertiary alcohols as nucleophiles and a large variety of epoxides, including 5α,6α-, 5β,6β- and 2α,3α-epoxysteroids, as substrates.
Solvent Microstructure Effect on Reaction Stereochemistry; Ring Opening of Chalcone Oxides
Durham, Dana,Kingsbury, Charles A.
, p. 923 - 930 (2007/10/02)
The stereochemistry and kinetics of acid-catalysed ring-opening reactions of epoxides are reported.Predominant inversion is found in the usual hydroxylic solvents.As the nucleophilicity of the solvent diminishes and acidity increases, the stereochemistry changes to predominant retention.Electron-donating substituents also tend to favour retention.In mixed solvents, the solvent microstructure is altered, leading to net retention for nucleophiles such as methanol.The exception is dioxane-methanol, which gives enhanced inversion.Molecular mechanics calculations indicate an electrostatic preference for the retention route, but a steric preference for inversion.The activation parameters indicate a negative entropy for both inversion and retention paths.Possible reasons are discussed for the entropy of the retention route being in the range normally found for A2 reactions.
