Stereocontrolled Creation of All-Carbon Quaternary Stereocenters by Organocatalytic Conjugate Addition of Oxindoles to Vinyl Sulfone
作者:Qiang Zhu、Yixin Lu
DOI:10.1002/anie.201003837
日期:2010.10.11
residues have been prepared (see scheme), and found to be very effective towards the asymmetric addition of 3‐alkyl‐oxindoles to 1,1‐bis(benzenesulfonyl)ethylene. This synthetic protocol has led to the enantioselective synthesis of 3‐alkyl‐3‐aryl‐disubstituted oxindoles and indolines with an all‐carbon quaternary stereogenic center.
Axially Chiral C2-Symmetric N-Heterocyclic Carbene (NHC) Palladium Complex-Catalyzed Asymmetric Fluorination and Amination of Oxindoles
作者:Rui Zhang、De Wang、Qin Xu、Jiajun Jiang、Min Shi
DOI:10.1002/cjoc.201200289
日期:2012.6
Chiral C2‐symmetric N‐heterocyclic carbene (NHC) palladium diaquo complex 5b prepared from (S)‐BINAM was found to be a fairly effective catalyst for the enantioselective asymmetric fluorination of oxindoles to give the corresponding products in moderate enantioselectivities along with good to excellent yields.
Enantioselective Fluorination of 2-Oxindoles by Structure-Micro-Tuned<i>N</i>-Fluorobenzenesulfonamides
作者:Fajie Wang、Juli Li、Qingyang Hu、Xianjin Yang、Xin-Yan Wu、Haoming He
DOI:10.1002/ejoc.201402072
日期:2014.6
attempts to fine-tune the reactivity and selectivity of N-fluorobenzenesulfonamide in fluorination reactions by changing the substituents on its phenyl rings. A series of N-fluorobenzenesulfonamides bearing substituents at the ortho, meta, and para positions were prepared, and were used in the enantioselectivefluorination of 2-oxindoles catalysed by chiral palladium complexes. Fluorinating reagents 1b
phase‐transfer reaction system can be applied to highly enantioselectiveconjugateaddition and aldol reactions under the influence of chiral bifunctional ammonium bromides as key catalysts. The structure of the chiral ammonium enolate intermediate is discussed based on the single‐crystal X‐ray structures of relevant ammonium salts and the importance of bifunctional design of catalyst is clearly explained in the