Synthesis of C2-Symmetric Benzimidazolium Salts and Their Application in Palladium-Catalyzed Enantioselective Intramolecular α-Arylation of Amides
作者:Weiping He、Wei Zhao、Bihui Zhou、Haifeng Liu、Xiangrong Li、Linlin Li、Jie Li、Jianyou Shi
DOI:10.3390/molecules21060742
日期:——
A series of C₂-symmetric chiral benzimidazoliumsalts, the precursor of N-heterocycliccarbeneligands, were designed and synthesized from 1,2-dibromobenzene. In situ prepared corresponding carbenes were tested in the asymmetric palladium-catalyzed intramolecular α-arylation of amides, affording chiral diarylmethanols with high yields and moderate enantioselectivities.
Palladium-Catalyzed Enantioselective α-Arylation and α-Vinylation of Oxindoles Facilitated by an Axially Chiral P-Stereogenic Ligand
作者:Alexander M. Taylor、Ryan A. Altman、Stephen L. Buchwald
DOI:10.1021/ja903880q
日期:2009.7.29
The enantioselective alpha-arylation and alpha-vinylation of oxindoles catalyzed by Pd and a biarylmonophosphine ligand with both axial and phosphorus-based chirogenicity is reported. The resultant quaternary carbon stereocenters are formed in high enantiomeric excess and the conditions tolerate a range of substitution on both the oxindole and the aryl/vinyl coupling partners.
Bulky Chiral Carbene Ligands and Their Application in the Palladium-Catalyzed Asymmetric Intramolecular α-Arylation of Amides
作者:E. Peter Kündig、Thomas M. Seidel、Yi-xia Jia、Gérald Bernardinelli
DOI:10.1002/anie.200703408
日期:2007.11.12
New Chiral N-Heterocyclic Carbene Ligands in Palladium-Catalyzed α-Arylations of Amides: Conformational Locking through Allylic Strain as a Device for Stereocontrol
作者:Yi-Xia Jia、Dmitry Katayev、Gérald Bernardinelli、Thomas M. Seidel、E. Peter Kündig
DOI:10.1002/chem.201000031
日期:——
Enders/Herrmann‐type chiral N‐heterocyclic carbene (NHC) ligands have been developed and applied in asymmetric palladium‐catalyzed intramolecular α‐arylations of amides. The best ligands feature the bulky tert‐butyl group and ortho‐substituted aryl groups at the stereogenic centers. Aryl bromides readily react at room temperature and aryl chlorides at 50 °C. The highly enantiomerically enriched (up