Steric effects in palladium-catalysed amination of aryl triflates and nonaflates with the primary amines PhCH(R)NH2 (R=H, Me)
作者:Rebecca E. Meadows、Simon Woodward
DOI:10.1016/j.tet.2007.11.074
日期:2008.2
A systematic study of the effects of aryl triflate and nonaflate structure on the yield of amination with the primary amines PhCH(R)NH2 (R=H, Me) under palladium catalysis has been carried out. High throughput screening indicated that a catalyst composed of X-Phos/Pd-2(dba)(3)/1.4-dioxane was optimal based on a model reaction of Ar(ORf) [R-f-T-f (SO2CF3) Nf (SO2(CF2)(3)CF3)] with PhCH2NH2. Comparisons of the reactivity of various ArOTf and ArONf [Ar=4-MePh, 2-naphthyl, 1-naphthyl, 2-PhC6H4] indicated that both ortho substitution in the aryl electrophile and at the alpha-position on the amine are detrimental to the coupling particularly when they occur in combination. Despite being formally a monodentate ligand use of X-Phos leads to only small degrees of racemisation when using (R)-PhCH(Me)NH2 (typically resulting in a reduction from 97 to 86-94% ee for the amine stereocentre). (c) 2007 Elsevier Ltd. All rights reserved.
Expanding Pd-Catalyzed C−N Bond-Forming Processes: The First Amidation of Aryl Sulfonates, Aqueous Amination, and Complementarity with Cu-Catalyzed Reactions
作者:Xiaohua Huang、Kevin W. Anderson、Danilo Zim、Lei Jiang、Artis Klapars、Stephen L. Buchwald
DOI:10.1021/ja035483w
日期:2003.6.1
The first general method for the Pd-catalyzedamination of aryl tosylates and benzenesulfonates was developed utilizing ligand 1, which belongs to a new generation of biaryl monophosphine ligands. In addition, the new catalyst system for the first time enables amidation of aryl arenesulfonates and aqueousamination protocols that do not necessitate the use of cosolvents. The substrate scope has been
Pd催化芳基甲苯磺酸酯和苯磺酸酯胺化的第一种通用方法是利用配体1开发的,该配体属于新一代联芳基单膦配体。此外,新的催化剂系统首次实现了芳基芳烃磺酸盐的酰胺化和不需要使用助溶剂的水性胺化方案。底物范围已显着扩大到包括含有伯酰胺和游离羧酸基团的芳基卤化物。在多功能基板的情况下,Pd 催化的胺化可以提供与 Cu 催化的 CN 键形成过程互补的选择性。