Acylative Kinetic Resolution of Alcohols Using a Recyclable Polymer-Supported Isothiourea Catalyst in Batch and Flow
作者:Rifahath Mon Neyyappadath、Ross Chisholm、Mark D. Greenhalgh、Carles Rodríguez-Escrich、Miquel A. Pericàs、Georg Hähner、Andrew D. Smith
DOI:10.1021/acscatal.7b04001
日期:2018.2.2
prepared and used for the acylative kinetic resolution of secondary alcohols. A wide range of alcohols, including benzylic, allylic, and propargylic alcohols, cycloalkanol derivatives, and a 1,2-diol, has been resolved using either propionic or isobutyric anhydride with good to excellent selectivity factors obtained (28 examples, s values up to 600). The catalyst can be recovered and reused by a simple filtration
Chiral dendrimers with three or six β-amino alcohols on hyperbranched hydrocarbon chain-ends were synthesized. These macromolecules can act as chiral catalysts for the enantioselective addition of dialkylzincs to aldehydes. The corresponding secondary alcohols are obtained in high enantiomeric excess (up to 86% e.e.).
Highly enantioselective addition of dialkylzincs to aldehydes using dendritic chiral catalysts with flexible carbosilane backbones
作者:Itaru Sato、Ryo Kodaka、Kenji Hosoi、Kenso Soai
DOI:10.1016/s0957-4166(02)00203-3
日期:2002.5
Chiral dendrimers bearing four or twelve chiral β-amino alcohols on the hyperbranched flexible carbosilane chain-ends act as efficient chiral catalysts for the enantioselectiveaddition of dialkylzinc to aldehydes to afford enantiomerically enriched sec-alcohols with up to 93% e.e.
Application of well-defined chain-end-functionalized polystyrenes with dendritic chiral ephedrine moieties as reagents for highly catalytic enantioselective addition of dialkylzincs to aldehydes
作者:Ashraf A. El-Shehawy、Kenji Sugiyama、Akira Hirao
DOI:10.1016/j.tetasy.2007.12.020
日期:2008.3
having a definite number of chiral ephedrine moieties dendritically distributed at the periphery of their hyperbranched chain-ends were evaluated as chiral catalysts for the enantioselectiveaddition of dialkylzinc reagents to aldehydes. These dendritic macromolecules worked well as homogeneous chiral catalysts and exhibited high catalytic activity and enantioselectivity very similar to those observed
Evaluating polymer-supported isothiourea catalysis in industrially-preferable solvents for the acylative kinetic resolution of secondary and tertiary heterocyclic alcohols in batch and flow
作者:Nitul Ranjan Guha、Rifahath M. Neyyappadath、Mark D. Greenhalgh、Ross Chisholm、Samuel M. Smith、Megan L. McEvoy、Claire M. Young、Carles Rodríguez-Escrich、Miquel A. Pericàs、Georg Hähner、Andrew D. Smith
DOI:10.1039/c8gc02020e
日期:——
acylative kinetic resolution of secondary and tertiary heterocyclic alcohols. In batch, the use of industrially-preferable solvents was investigated, with dimethyl carbonate proving to be most generally-applicable. Significantly, the HyperBTM-derived immobilised catalysts were readily recycled, with no loss in either activity or selectivity. In addition to the kinetic resolution of secondary benzylic, propargylic