Mild Conditions for Copper-CatalysedN-Arylation of Pyrazoles
作者:Henri-Jean Cristau、Pascal P. Cellier、Jean-Francis Spindler、Marc Taillefer
DOI:10.1002/ejoc.200300709
日期:2004.2
Copper-catalysed N-arylation of pyrazoles with aryl or heteroaryl bromides or iodides, which can include functional substituents, was performed under the mildest conditions yet described, with excellent yields and selectivity, by the use as catalyst of a combination of cuprous oxide with a set of inexpensive, chelating oxime-type ligands not previously known to promote such reactions. Other original
Cation Radical Accelerated Nucleophilic Aromatic Substitution via Organic Photoredox Catalysis
作者:Nicholas E. S. Tay、David A. Nicewicz
DOI:10.1021/jacs.7b10076
日期:2017.11.15
Nucleophilicaromaticsubstitution (SNAr) is a direct method for arene functionalization; however, it can be hampered by low reactivity of arene substrates and their availability. Herein we describe a cation radical-accelerated nucleophilicaromaticsubstitution using methoxy- and benzyloxy-groups as nucleofuges. In particular, lignin-derived aromatics containing guaiacol and veratrole motifs were
A directing/protecting‐group‐free synthesis of 1,3,4,5‐tetraaryl‐substituted pyrazoles was achieved throughfour transition metal‐catalyzed directarylations. Various pyrazoles with four different aryl rings were obtained using readily available reagents from an unsubstitutedpyrazole. Two aryl‐substituted pyrazoles showed intense violet fluorescence, high quantum yields (Φf=0.68, 0.64), and large