Room-Temperature CuI-Catalyzed Amination of Aryl Iodides and Aryl Bromides

Abstract

A general and effective CuI/N',N'-diaryl-1H-pyrrole-2-carbohydrazide catalyst system was developed for the amination of aryl iodides and bromides at room temperature with good chemoselectivity between -OH and -NH groups. Only 5 mol % of CuI and ligands was needed in this protocol to effect the amination of various aryl bromides and aryl iodides with a wide range of aliphatic and aryl amines (1.3 equiv).

An Effective Heterogeneous Copper Catalyst System for C–N Coupling and Its Application in the Preparation of 2-Methyl-4-methoxydiphenylamine (MMDPA)

“…After exploring the reaction parameters such as solvents, copper sources, bases, and the corresponding proportions (Table S2, SI) we established the optimized reaction conditions as consisting of 5 mol% of PSAP (30 mg, size > 100 mesh) and 5 mol% of CuI, aryl bromides (100 mol%), amines (150 mol%) and K 3 PO 4 (200 mol%) in diethylene glycol (DEG) at 70 °C (Table S2, SI, entry 31). As expected, this heterogeneous catalyst system was almost the same as our previously reported homogeneous counterpart 19 except for the need for higher reaction temperature.…”

“…This result inspired us to continue our examination of the scope and generality of the C-N coupling reaction, although the catalytic performance of the heterogeneous catalyst system decreased in comparison with its original homogeneous counterpart with respect to reaction temperature and reaction time. 19 Scheme…”

Triarylmethane Fluorophores Resistant to Oxidative Photobluing

“…In a recent work by Zhu and Wan, 33 an Ullmann-type amination of aryl bromides and iodides with secondary and primary amines, including 1-aminoadamantane, under exceptionally mild conditions (5 mol % of Cu catalyst, K 3 PO 4 base in diethylene glycol, rt to 60 °C) has been reported. Employing this catalytic system, upon optimization (Table S3) we were able to achieve double amination with primary N - tert -alkylamines on a diverse variety of 3′,6′-dibromo- and 3′,6′-diiodofluorans prepared as described above (Figure 3).…”

Synthesis of N‐Aryl‐ and N‐Alkenylhydrazides through C(sp2)−N Bond Construction

“…applied Ma's conditions in the preparation of N ’, N ’‐diaryl‐1 H ‐pyrrole‐2‐carbo‐hydrazide 139 using 1 H ‐pyrrole‐2‐carbohydrazide 138 and excess aryl iodides (Scheme 29). [57] They utilized hydrazides 139 as ligands in Ullmann‐type coupling of aryl halides with amines in good yields with high chemoselectivity. Huang installed the hydrazide scaffold onto a polystyrene scaffold to obtain a heterogeneous ligand N ‐((4‐(aminomethyl)‐naphthalen‐1‐yl)‐ N‐ (phenyl‐1H‐pyrrole)‐2‐carbo‐hydrazide (PSAP), which could be recyclable after Ullmann‐type coupling [58]…”