A research team led by Prof. CHEN Qing'an from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has realized Nozaki-Hiyama-Kishi (NHK) reaction of alkenes and arylhalides under Ni/Cr cocatalysis.
Their findings were published in ACS Catalysis on Jan. 31.
Nozaki-Hiyama-Kishi (NHK) reaction is important in synthetic chemistry, which features Ni/Cr-catalyzed coupling between aldehydes and arylhalides.
However, compared with conventional aldehydes, alkenes cannot form thermodynamically favored metal-oxygen bonds, thus their NHK reactions have not been achieved yet.
In this study, the researchers realized NHK reaction of 1,3-dienes and arylhalides with the assistance of redox active bis(imino)pyridine (PDI) ligand, through which diarylated products can be obtained with high regio- and stereoselectivities. "The key to success relies on the involvement of radical process. CrCl2 serves as a single-electron reductant for the formation of Ni(I) species and aryl radical," said Prof. CHEN.
Besides, the resulting diarylated products can be easily transformed into valuable polyaryl thiophene and naphthalene that are interesting building blocks for the manufacture of advanced functional materials.
"This work is an important complement to NHK reaction. It also provides a paradigm for exploring new functionalization of dienes," said Prof. CHEN.
The research was supported by Dalian Outstanding Young Scientific Talent and the National Natural Science Foundation of China.