Cesium Carbonate Promoted Direct Arylation of Hydroxylamines and Oximes with Diaryliodonium Salts

Abstract

A transition‐metal‐free approach for the arylation of hydroxylamines and oximes with diaryliodonium salts was developed. The reaction proceeded smoothly at room temperature in the presence of cesium carbonate. As a result, a wide range of N‐ and O‐arylated hydroxylamines were synthesized in good to excellent yields (45–98 %).

Aryl Transfer Selectivity in Metal‐Free Reactions of Unsymmetrical Diaryliodonium Salts

“…Steric effects also have a prominent influence on aryl transfer selectivity in these reactions and an ortho-effect is observed in these cases. The reaction of 46 [13] or hydroxamic acid 54 [15] with 14b leads to preferential transfer of the mesityl group in both cases (Scheme 9). However, note that the ratio of aryl transfer depends on the nucleophile.…”

Recent Advances in the Arylation and Alkenylation of N–O Bonds

“…In 2014, Han and Wang provided a cesium carbonate mediated approach to the O-arylation of oximes and diaryliodonium salts directly under mild conditions (Scheme 16). 22 Many substituents, on both substrates, were compatible, and the O-aryl oxime ethers were obtained efficiently in good to excellent yields.…”

Diaryliodonium Salts in Organic Syntheses: A Useful Compound Class for Novel Arylation Strategies

“…Another approach for the N-arylation with the aid of diaryliodonium salts was demonstrated by Wang et al 24 They demonstrated that the arylation of hydroxylamines (21) proceeded smoothly at room temperature in the presence of cesium carbonate (Scheme 11) and the desired products (22) were isolated in good to excellent yields. The N-arylation of non-aromatic systems such as alkyl-amides is also possible with the utilization of diaryliodonium salts.…”

“…Another approach for the N-arylation with the aid of diaryliodonium salts was demonstrated by Wang et al 29 They demonstrated that the arylation of hydroxylamines 27 pro-…”