Copper-catalyzed transformation of alkyl nitriles to N-arylacetamide using diaryliodonium salts

Abstract

In this study, a simple and efficient method for the copper-catalyzed redox-neutral transformation of alkyl nitriles using eco-friendly diaryliodonium salts and leading to N-arylacetamides was investigated.

A Mechanistic Study of the Cu‐catalyzed N‐arylation of Hydantoin with Aryl(TMP)iodonium Salts

“…[16][17][18][19][20][21][22][23][24][25][26] However, the detailed mechanistic understanding of the copper-catalyzed cross-couplings with diaryliodonium salts is modest and mostly limited to CÀ H functionalization reactions with symmetrical salts (Ar 1 = Ar 2 , Scheme 1a). [27][28][29][30][31][32] While these salts have been extensively used to avoid selectivity issues in arene transfer reactions, unsymmetrical salts (Ar 1 ¼ 6 Ar 2 , Scheme 1b) are preferred when expensive aryl groups are the target, as they allow for the use of a cheaper auxiliary (nontransferred) group (Ar 2 in Scheme1b). In addition, unsymmetrical diaryliodonium salts facilitate tuning of the electronic and steric properties of the auxiliary group to facilitate transfer of the desired arene, which may be needed for the arylation of difficult substrates.…”

“…This step is also assumed to be the first in the few computational studies of Cu-catalyzed CÀ H arylation reactions with diaryliodonium salts. [30][31][32] Closely related to the aryl(Mes)iodonium salts are the aryl(TMP)iodonium salts (TMP = 2,4,6-trimethoxyphenyl). Recent interests in the use of aryl(TMP)iodonium salts can be attributed to their excellent selectivity in aryl transfer reactions with various nucleophiles.…”

“…Particularly, the use of copper as transition metal has proven to facilitate the transfer efficiently [16–26] . However, the detailed mechanistic understanding of the copper‐catalyzed cross‐couplings with diaryliodonium salts is modest and mostly limited to C−H functionalization reactions with symmetrical salts (Ar 1 =Ar 2 , Scheme 1a) [27–32] . While these salts have been extensively used to avoid selectivity issues in arene transfer reactions, unsymmetrical salts (Ar 1 ≠Ar 2 , Scheme 1b) are preferred when expensive aryl groups are the target, as they allow for the use of a cheaper auxiliary (non‐transferred) group (Ar 2 in Scheme1b).…”

“…In their study, a combination of DFT calculations and experiments suggested a Cu(I)/Cu(III)‐catalytic cycle, starting with the oxidative addition of the aryl(Mes)iodonium salt. This step is also assumed to be the first in the few computational studies of Cu‐catalyzed C−H arylation reactions with diaryliodonium salts [30–32] . Closely related to the aryl(Mes)iodonium salts are the aryl(TMP)iodonium salts (TMP=2,4,6‐trimethoxyphenyl).…”