Cu (I)-Catalyzed C-C and C-N Coupling Reactions from a Theoretical Point of View

Subject Areas :

Fatemeh Zarkoob ¹ , Alireza Ariafard ^{2 *}

1 - Student/Islamic Azad University of Central Tehran Branch
2 - Member of Science Faculty/Islamic Azad University of Central Tehran Branch

Received: 2020-07-31 Accepted : 2020-11-17 Published : 2020-02-20

Keywords: Oxidative Addition, density functional theory, SN2, Deprotonation, Concerted Reaction, Reductive Elimination,

Abstract :

Density functional theory was used to investigate Cu(I) catalytic mechanism for the formation of C-C and C-N bonds by heteroarenes in the presence of aryl halides and alkyl halides. The mechanism cycle started with deprotonating C-H and N-H bonds on heteroarenes. Our studies showed that deprotonation occurs through a five-centered transition structure in which the interaction between the nitrogen atoms in the heteroarene with copper caused stability and reduced the energy barrier. Finally, C-C or C-N bonds were formed in the presence of aryl halide or alkyl halide. When an aryl halide was added (C(sp2)–X), the mechanism proceeded through the concerted reaction through oxidative addition of Cu (I). After the transient state, reductive elimination occurred without an energy barrier and led to formation of the product. Our theoretical calculations showed that the mechanism for alkyl halides (C(sp3)-X) differs from aryl halides. The overall mechanism in the presence of alkyl halides is SN2 reaction. However, C-C and C-N bonds are formed by SN2 respectively through oxidative addition of copper and C-N coupling reaction. In both paths, the product was formed without an energy barrier.