ligands were designed and synthesized. The rhodium complexes with the ligands were applied to the asymmetric transfer hydrogenation of broad range of long-chained aliphatic ketoesters in neatwater. Quantitative conversion and excellent enantioselectivity (up to 99% ee) was observed for α-, β-, γ-, δ- and ε-ketoesters as well as for α- and β-acyloxyketone using chiral surfactant-type catalyst 2. The CH/π
A novel ABBⲠ3 component reaction (3-CR) system based on the organocatalyzed homoaldolic condensation of α-ketoesters in the presence of terminal conjugated alkynoates is described.
Asymmetric Henry Reaction Catalyzed by <i>C</i><sub>2</sub>-Symmetric Tridentate Bis(oxazoline) and Bis(thiazoline) Complexes: Metal-Controlled Reversal of Enantioselectivity
作者:Da-Ming Du、Shao-Feng Lu、Tao Fang、Jiaxi Xu
DOI:10.1021/jo050097d
日期:2005.4.1
C2-symmetric tridentate bis(oxazoline) and bis(thiazoline) ligands with a diphenylamine backbone have been investigated in the catalytic asymmetric Henry reaction of α-keto esters with different Lewisacids. Their Cu(OTf)2 complexes furnished S enantiomers, while Et2Zn complexes afforded R enantiomers, both of them with higher enantioselectivities (up to 85% ee). Reversal of enantioselectivity in asymmetric
A Substrate-Based Folding Process Incorporating Chemodifferentiating ABB′ Three-Component Reactions of Terminal Alkynoates and 1,2-Dicarbonyl Compounds: A Skeletal-Diversity-Oriented Synthetic Manifold
reaction (3CR)-based folding process that is able to generate complexity and skeletal diversity is described. The process utilizes chemodifferentiating organocatalyzed ABB' 3CRs of a terminal conjugated alkynoate (building block) with alpha-dicarbonyl compounds (diversity-generating blocks) to generate an array of different molecular topologies (gamma-lactones, linear propargylic enol ethers, or 1,3-dioxolane
An effective and mild electrocatalytic procedure for the removal of 1,3-dithiane protecting groups
作者:Martin Platen、Eberhard Stekhan
DOI:10.1016/s0040-4039(01)85541-6
日期:1980.1
The 1,3-dithiane protectinggroup can effectively be removed by indirect electrochemical oxidation under extremely mild conditions, if catalytic amounts of tris(p-tolyl)amine are used as homogeneous electron transfer agents.