“On Water’’ Promoted Ullmann-Type C–N Bond-Forming Reactions: Application to Carbazole Alkaloids by Selective N-Arylation of Aminophenols

Abstract

The Ullmann-type cross coupling of a variety of aromatic, aliphatic amines with aryl halides is reported using a CuI-based catalytic system in combination with an easily accessible prolinamide ligand in aqueous media. The method is mild and tolerant to air, moisture, and a wide range of functional groups, providing a novel way to access a variety of aminated products. Secondary amines like heteroaromatic amines and nucleobases have also been used, affording the corresponding coupling products in good to excellent yields. Moreover, this method has been employed for chemoselective C-N arylation of aminophenols and further utilized for the synthesis of carbazole natural products, avoiding the protection and deprotection steps.

Recent Advances and Prospects of Organic Reactions “On Water”

“…An on water chemistry for the Ullmann‐type cross‐coupling of amines with aryl halides using CuI as catalyst and prolinamide ligand was reported (Scheme ) . Different aromatic and heteroaromatic secondary amines, aliphatic amines and nucleobases like cytosine and uracil were reacted with various aryl halides (iodides and bromides) to afford the product in moderate to good yields.…”

N‐(4‐Thiazolylmethyl)Morpholine N‐Oxide as N,O‐Bidentate Ligand for Copper‐Catalyzed Ullmann‐Type N‐Arylation of Azoles/Amines with Aryl Halides

“…In this protocol, the azeotrope consist of furfuryl alcohol and water was easily recovered by distillation and reused again. At the same year, Dash J. and Xuan, L. documented the Ullmann‐type coupling of amines/N−H heterocycles with aryl halides using CuI/triazolylprolinamide or CuI/N,N‐dimethyl‐D‐glucosamine as catalysts, respectively (Figure B). Very recently, Peng, J. and coworkers described the synthesis of multisubstituted indoles via copper(I)‐catalyzed tandem Ullmann‐type reaction/cross‐dehydrogenative coupling of enamines with aryl iodides using Johnphos as supporting ligands (Figure B) .…”

Preparation, Characterization and Application of Copper Schiff base Complex Supported on MCM‐41 as a Recyclable Catalyst for the Ullmann‐type N‐arylation Reaction

“…The transition‐metal‐catalyzed C−N bond formation, known as N‐arylation reaction, has attracted much attention in organic synthesis. It is one of the most useful methods for the construction of N‐aryl amines, which constitute important structural units in various biologically active pharmaceutical ingredients and natural products . The most promising method in the literature for the N‐arylation reaction is Copper‐catalyzed Ullmann‐type transformation.…”

“…It is one of the most useful methods for the construction of N-aryl amines, which constitute important structural units in various biologically active pharmaceutical ingredients and natural products. [1][2][3][4][5][6][7][8] The most promising method in the literature for the N-arylation reaction is Coppercatalyzed Ullmann-type transformation. Unfortunately, this method requires a stoichiometric amount of copper catalyst at high temperatures, which eventually produce a large amount of hazardous copper-based waste and are thus not considered to be environmentally benign and economic processes.…”