4427-56-9Relevant articles and documents
Enantioselective Kinetic Resolution/Desymmetrization of Para-Quinols: A Case Study in Boronic-Acid-Directed Phosphoric Acid Catalysis
Huang, Banruo,He, Ying,Levin, Mark D.,Coelho, Jaime A. S.,Bergman, Robert G.,Toste, F. Dean
supporting information, p. 295 - 301 (2019/11/03)
A chiral phosphoric acid-catalyzed kinetic resolution and desymmetrization of para-quinols operating via oxa-Michael addition was developed and subsequently subjected to mechanistic study. Good to excellent s-factors/enantioselectivities were obtained over a broad range of substrates. Kinetic studies were performed, and DFT studies favor a hydrogen bonding activation mode. The mechanistic studies provide insights to previously reported chiral anion phase transfer reactions involving chiral phosphate catalysts in combination with boronic acids. (Figure presented.).
Zirconia-modified superacid UDCaT-5: An efficient and versatile catalyst for alkylation reactions under solvent-free conditions
Yadav, Ganapati D.,Pathre, Ganesh S.
, p. 2684 - 2691 (2008/12/22)
UDCaT-5, a modified version of zirconia, efficiently catalyzes alkylation of phenols with alcohols under environmentally safe, heterogeneous reaction conditions with high selectivity and in excellent yields. The high content present in UDCaT-5 with preservation of tetragonal phase of zirconia was responsible for the superactivity. Several phenolic compounds carrying either electron-sulfer releasing or electron-withdrawing substituents in the ortho, meta, and para positions afforded high yields of the products. Copyright Taylor & Francis Group, LLC.
Lewis Acids Catalysed Fries Rearrangement of Isopropylcresol Esters
Martin, Robert,Demerseman, Pierre
, p. 227 - 236 (2007/10/02)
In the course of the Fries rearrangement, aluminium chloride frequently induces migration or elimination of alkyl groups.The results obtained with titanium tetrachloride for the synthesis of vicinal o-hydroxyketones are compared with those obtained with aluminium chloride for some aliphatic and aromatic esters of isopropylcresols.In order to understand the migration and elimination processes occurring, the stabilities of the o-hydroxyketones are studied in the presence of aluminium chloride at different temperatures.Furthermore, all-vicinal o-hydroxyketones were prepared by the Fries rearrangement of 6-tert-butyl-p-thymol with titanium tetrachloride.