Click-Connected Ligand Scaffolds: Macrocyclic Chelates for Asymmetric Hydrogenation
摘要:
Click chemistry is used to construct ligand scaffolds for a series of chiral diphosphites. Enantioselectivity as high as 97% ee is obtained using these click ligands in rhodium-catalyzed asymmetric hydrogenation. Control experiments and spectroscopic data suggest that a 16-membered PP-macrocyclic Rh(I) chelate is formed.
A Highly Active Catalyst for Huisgen 1,3-Dipolar Cycloadditions Based on the Tris(triazolyl)methanol−Cu(I) Structure
作者:Salih Özçubukçu、Erhan Ozkal、Ciril Jimeno、Miquel A. Pericàs
DOI:10.1021/ol9018776
日期:2009.10.15
A new tris(1-benzyl-1H-1,2,3-triazol-4-yl)methanol ligand 3 has been prepared by a triple Cu(I)-catalyzed alkyne-azide 1,3-dipolar cycloaddition (CuAAC). Ligand 3 forms a stable complex with CuCl, which catalyzes the Huisgen 1,3-dipolar cycloaddition on water or under neat conditions. Low catalyst loadings, short reaction times at room temperature, and compatibility with free amino groups make 3-CuCl an outstanding catalyst for CuAAC.