Chiral N-Heterocyclic Carbene Borane Complexes: Synthesis and Structural Analysis
作者:Dipshikha Banerjee、Céline Besnard、E. Peter Kündig
DOI:10.1021/om201087n
日期:2012.1.23
A new family of chiralN-heterocycliccarbene borane complexes was synthesized starting from their corresponding imidazoliumsalts. The complexes were fully characterized. X-ray crystal structures of the complexes were obtained.
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
Diaminophosphine Oxide Ligand Enabled Asymmetric Nickel-Catalyzed Hydrocarbamoylations of Alkenes
作者:Pavel A. Donets、Nicolai Cramer
DOI:10.1021/ja406730t
日期:2013.8.14
Chiral trivalent phosphorus species are the dominant class of ligands and the key controlling element in asymmetric homogeneous transition-metalcatalysis. Here, novel chiral diaminophosphine oxide ligands are described. The arising catalyst system with nickel(0) and trimethylaluminum efficiently activates formamide C-H bonds under mild conditions providing pyrrolidones via intramolecular hydrocarbamoylation