A PEG/copper(I) halide cluster as an eco-friendly catalytic system for C-N bond formation

作者：Li, Cheng-An; Ji, Wei; Qu, Jian; Jing, Su^*; Gao, Fei; Zhu, Dun-Ru^*

来源：Dalton Transactions, 2018, 47(22): 7463-7470.

DOI：10.1039/c8dt01310a

• CROSS-COUPLING REACTIONS
• COPPER IODIDE CLUSTERS
• MECHANOCHROMIC LUMINESCENCE
• MEDICINAL CHEMISTS
• CRYSTAL-STRUCTURES
• LIGANDS SYNTHESIS
• ARYL IODIDES
• ULLMANN
• MECHANISM
• ARYLATION

The catalytic activities of eight copper(I) halide clusters assembled from copper(I) halide and ferrocenyl-telluroethers, 1-8, were investigated in C-N formation under various conditions. A catalytic procedure using poly(ethylene glycol) (PEG-400) as a greener alternative organic solvent has been developed. The PEG-400/5 system can achieve 99% targeted yield with a mild reaction temperature and short reaction time. After the isolation of the products by extraction with diethyl ether, this PEG-400/cluster system could be easily recycled. Spectroscopic studies elucidate a stepwise mechanism: firstly, proton-coupled electron transfer (PCET) involving the transfer of an electron from Cu2+ and a proton from imidazole results in the formation of a labile penta-coordinated Cu2+ and aryl radical; the following effective electron transfer from the ferrocene unit reduces Cu2+ and forms the target product; finally, the ferrocenium unit is reduced by the I- anion. The merits of this eco-friendly synthesis are the efficient utilization of reagents and easy recyclability.

• 出版日期2018-6-14
• 单位南京大学