Palladium/Zinc Co‐Catalyzed Asymmetric Hydrogenation of γ‐Keto Carboxylic Acids
作者:Keyang Zhang、Xuexin Zhang、Jingchao Chen、Zixiu Liu、Chunxiang Pan、Yuanbin Zhu、Shiyuan Wu、Baomin Fan
DOI:10.1002/asia.202100244
日期:2021.5.17
A palladium‐catalyzed asymmetric hydrogenation of levulinic acid has been successful developed by using Zn(OTf)2 as co‐catalyst. The present method not only has provided a strategy in the palladium‐catalyzed asymmetric hydrogenation of ketone, but also allowed the preparation of a wide range of chiral γ‐valerolactones in good yields with excellent enantioselectivities.
An asymmetrichydrogenation of aroylacrylic acidscatalyzed by RuPHOX-Ru catalyst has been developed, affording the corresponding chiral γ-lactones in high yields and with up to 93% ee. The methodology has the advantage of utilizing easily accessible substrates and has therefore expand the scope of the resulting chiral γ-lactones. Furthermore, high catalytic efficiency was achieved in that the reduction
Ni-Catalyzed Asymmetric Hydrogenation of Aromatic Ketoacids for the Synthesis of Chiral Lactones
作者:Chen-Qiang Deng、Jin Deng
DOI:10.1021/acs.orglett.2c00608
日期:2022.4.8
asymmetric hydrogenation of aromatic γ- and δ-ketoacids has been developed, affording a series of γ- and δ-aryl lactones in high yields and excellent enantioselectivities (≤98% ee). The hydrogenation could occur smoothly on a gram scale with 0.05 mol % catalyst loading (S/C = 2000). This protocol provides an efficient and practical approach for accessing chiral lactones with important potential applications
3,4-Dichlorophenacylchloride was reduced with whole cell biocatalysts to give the (R)- or (S)-chrorohydrine in high yields and good to high enantiomeric excess. Yields and enantiomeric purity of the (S)-enantiomer were increased to 95 and >98%, respectively, using growing cells from Geotrichum candidum (CBS 233.76) in the presence of hydrophobic adsorbing resins at 4 g/l. The latter compound was transformed into (R)-3,4-dichlorophenylbutanolide, intermediate in the synthesis of (+)-cis-1S,4S-sertraline. (C) 1999 Elsevier Science Ltd. All rights reserved.