N,O- vs N,C-Chelation in Half-Sandwich Iridium Complexes: A Dramatic Effect on Enantioselectivity in Asymmetric Transfer Hydrogenation of Ketones
作者:Gang Zhou、Ahmed H. Aboo、Craig M. Robertson、Ruixia Liu、Zhenhua Li、Konstantin Luzyanin、Neil G. Berry、Weiping Chen、Jianliang Xiao
DOI:10.1021/acscatal.8b02068
日期:2018.9.7
to a N,C- or N,O-chelated Cp*Ir(III) complex, depending on whether or not water was present in the reaction. While derived from the same precursor, these two complexes behaved in a dramatically different manner in asymmetric transfer hydrogenation (ATH) of ketones by formic acid, with the N,O-chelated complex being much more selective and active. The sense of asymmetric induction is also different, with
the corresponding ketone using 2-propanol as hydrogen donor or by enantioselectiveoxidationthrough kinetic resolution of the rac-alcohol using acetone as hydrogen acceptor employing whole lyophilized cells of Rhodococcus ruber DSM 44541. The microbialoxidation/reduction system exhibits not only excellent stereo- and enantioselectivity but also a broad substrate spectrum. Due to the exceptional tolerance
Synthesis, characterization, and organocatalytic application of chiral ionic liquids derived from (<i>S,R</i>)-noscapine
作者:Nirmaljeet Kaur、Harish Kumar Chopra
DOI:10.1080/00397911.2017.1384842
日期:2018.1.2
ABSTRACT (S,R)-Noscapine, a phthalideisoquinoline alkaloid has been used as precursor for the synthesis of chiral ionic liquids (CILs). Noscapine based CILs have been synthesized from reaction between (S,R)-noscapine and methyl iodide in acetonitrile at room temperature. The synthesized CILs have been characterized by 1H NMR, 13C NMR, EI-MS, and polarimetry techniques. These CILs have been used as
Highly enantioselective double reduction of phenylglyoxal to ( R )-1-phenyl-1,2-ethanediol by one NADPH-dependent yeast carbonyl reductase with a broad substrate profile
作者:Zhe Li、Weidong Liu、Xi Chen、Shiru Jia、Qiaqiang Wu、Dunming Zhu、Yanhe Ma
DOI:10.1016/j.tet.2013.02.085
日期:2013.4
Pichia pastoris GS115 were evaluated with a series of carbonyl compounds including aryl aldehydes, ketones, α- and β-ketoesters. This recombinant enzyme possessed a broad substrate profile with the ability of reducing both aldehydes and ketones. Especially, the enzyme catalyzed the double reduction of phenylglyoxal to (R)-1-phenyl-1,2-ethanediol with 99% yield and 99% ee by coupling with d-glucose dehydrogenase
Multienzyme One-Pot Cascade for the Stereoselective Hydroxyethyl Functionalization of Substituted Phenols
作者:Stefan E. Payer、Hannah Pollak、Benjamin Schmidbauer、Florian Hamm、Filip Juričić、Kurt Faber、Silvia M. Glueck
DOI:10.1021/acs.orglett.8b02058
日期:2018.9.7
The operability and substrate scope of a redesigned vinylphenol hydratase as a single biocatalyst or as part of multienzyme cascades using either substituted coumaric acids or phenols as stable, cheap, and readily available substrates are reported.