54522-91-7Relevant articles and documents
Well-defined silica-supported zirconium-benzyl cationic species: Improved heterogenization of single-site polymerization catalysts
Popoff, Nicolas,Macqueron, Beno?t,Sayhoun, Wissam,Espinas, Jeff,Pelletier, Jérémie,Boyron, Olivier,Boisson, Christophe,Merle, Nicolas,Szeto, Kai C.,Gauvin, Régis M.,De Mallmann, Aimery,Taoufik, Mostafa
, p. 888 - 895 (2014)
Zr(CH2Ph)4 (1) was grafted onto a recently disclosed hybrid material based on amorphous silica that features unique phenol grafting sites {[(≡SiO)2(AlOC6H4OH)(Et 2O)] (H)}. A monopodal trib
Catalytic Enantioselective [2,3]-Rearrangements of Allylic Ammonium Ylides: A Mechanistic and Computational Study
West, Thomas H.,Walden, Daniel M.,Taylor, James E.,Brueckner, Alexander C.,Johnston, Ryne C.,Cheong, Paul Ha-Yeon,Lloyd-Jones, Guy C.,Smith, Andrew D.
supporting information, p. 4366 - 4375 (2017/04/04)
A mechanistic study of the isothiourea-catalyzed enantioselective [2,3]-rearrangement of allylic ammonium ylides is described. Reaction kinetic analyses using 19F NMR and density functional theory computations have elucidated a reaction profile
Asymmetric 1,2-Perfluoroalkyl Migration: Easy Access to Enantioenriched α-Hydroxy-α-perfluoroalkyl Esters
Wang, Pan,Feng, Liang-Wen,Wang, Lijia,Li, Jun-Fang,Liao, Saihu,Tang, Yong
supporting information, p. 4626 - 4629 (2015/04/27)
This study has led to the development of a novel, highly efficient, 1,2-perfluoro-alkyl/-aryl migration process in reactions of hydrate of 1-perfluoro-alkyl/-aryl-1,2-diketones with alcohols, which are promoted by a Zn(II)/bisoxazoline and form α-perfluoro-alkyl/-aryl-substituted α-hydroxy esters. With (-)-8-phenylmenthol as the alcohol, the corresponding menthol esters are generated in high yields with excellent levels of diastereoselectivity. The mechanistic studies show that the benzilic ester-type rearrangement reaction takes place via an unusual 1,2-migration of electron-deficient trifluoromethyl group rather than the phenyl group. The overall process serves as a novel, efficient, and simple approach for the synthesis of highly enantioenriched, biologically relevant α-hydroxy-α-perfluoroalkyl carboxylic acid derivatives.
Insights into the asymmetric heterogeneous catalysis in porous organic polymers: Constructing A TADDOL-Embedded chiral catalyst for studying the structure-activity relationship[ ]
An, Wan-Kai,Han, Man-Yi,Wang, Chang-An,Yu, Si-Min,Zhang, Yuan,Bai, Shi,Wang, Wei
, p. 11019 - 11028,10 (2014/12/09)
Construction of porous organic polymers (POPs) as asymmetric catalysts remains as an important but challenging task. Herein, we exploit the "bottom-up" strategy to facilely synthesize an α,α, α,α-tetraaryl-1,3-dioxolane-4,5-dimethanol (TADDOL)-based chiral porous polymer (TADDOL-CPP) for highly efficient asymmetric catalysis. Constructed through the covalent linkages among the three-dimensional rigid monomers, TADDOL-CPP possesses hierarchical porous structure, high Brunauer-Emmett-Teller (BET) surface area, together with abundant and uniformly-distributed chiral sites. In the presence of [Ti(OiPr)4], TADDOL-CPP acts as a highly efficient and recyclable catalyst in the asymmetric addition of diethylzinc (Et2Zn) to aromatic aldehydes. Based on the direct observation of the key intermediates, the reaction mechanism has been revealed by solid-state 13C magic-angle spinning (MAS) NMR spectroscopy. In combination with the catalytic testing results, characterization on the working catalyst provides further information for understanding the structure-activity relationship. We suggest that the catalytic activity of TADDOL-CPP is largely affected by the structural rigidity, cooperative catalysis, local chiral environment, and hierarchical porous framework. We expect that the information obtained herein will benefit to the designed synthesis of robust POP catalysts toward practical applications.
