Transition-Metal-Free N-Arylation of N-Methoxysulfonamides and N,O-Protected Hydroxylamines with Trimethoxyphenyliodonium (III) Acetates

Abstract

Trimethoxyphenyl (TMP) iodonium(III) acetate functionated as an efficient arylation reagent for N,O-protected hydroxylamines, generating aniline derivatives in the absence of transition metal catalysts. Various N-methoxysulfonamides participated in the amination reaction to produce the corresponding N-methoxysulfonylanilines. This amination reaction was compatible with several protecting groups, including Troc (2,2,2-trichloroethoxycarbonyl), Cbz (benzyloxycarbonyl), Boc (tert-butoxycarbonyl), benzyl, acetyl, and silyl groups. This method uses TMP-iodonium(III) acetate and efficiently synthesizes various aniline derivatives, that are versatile synthetic intermediates for functional organic molecules.

Transition Metal‐FreeO‐Arylation ofN‐Alkoxybenzamides Enabled by Aryl(trimethoxyphenyl)iodonium Salts

“…Our group recently reported an efficient approach to the N ‐arylation of N ‐alkoxy‐sulfonamides/‐carbamates using aryl(trimethoxyphenyl(TMP))iodonium acetates under metal‐free conditions [24] . Notably, the reaction of N ‐alkoxybenzamides under the same conditions switched the chemoselectivity to provide the O ‐arylation product with good‐to‐excellent selectivity (Scheme 1e).…”

“…Initially, the reaction of N ‐methoxybenzamide 1 a‐OMe with Ph(TMP)iodonium salt ( 2 a ) was performed under the optimized conditions for the arylation of N ‐alkoxysulfonamides [24] . The O ‐phenylated product 3 aa‐OMe was fabricated in 60% yield along with 40% of N ‐arylated product 4 aa‐OMe (Table 1, entry 1).…”

“…[21][22][23] Our group recently reported an efficient approach to the N-arylation of N-alkoxy-sulfonamides/-carbamates using aryl(trimethoxyphenyl(TMP))iodonium acetates under metal-free conditions. [24] Notably, the reaction of N-alkoxybenzamides under the same conditions switched the chemoselectivity to provide the O-arylation product with good-to-excellent selectivity (Scheme 1e). Considering our long-term interest in the arylation of diverse nucleophiles using aryl(TMP)iodonium salts, [25] we herein report an efficient and sustainable protocol for the chemoselective O-arylation of N-alkoxyarylamides under transition metal-free conditions in the presence of aryl(TMP)iodonium salts.…”

“…Initially, the reaction of N-methoxybenzamide 1 a-OMe with Ph(TMP)iodonium salt (2 a) was performed under the optimized conditions for the arylation ofNalkoxysulfonamides. [24] The O-phenylated product 3 aa-OMe was fabricated in 60% yield along with 40% of N-arylated product 4 aa-OMe (Table 1, entry 1). Screening of iodonium salts with various counter anions (X) indicated the importance of OAc and OTs ligands over OTf, OCOCF 3 , and BF 4 (Table 1, entries 1-3; Table S1).…”

Reaction of Diaryliodonium Salts with Potassium Alkyl Xanthates as an Entry Point to Accessing Organosulfur Compounds

“…Moreover, transition-metal catalysts are expensive and toxic, suffer from sustainability issues, and may leave difficult-to-remove impurities in the final products . In recent years, carbon–heteroatom bond-forming arylations with diaryliodonium salts under transition-metal-free conditions have emerged as a powerful and sustainable alternative and complement to the existing workhorse methods . Many robust protocols for the arylation of various heteroatom nucleophiles utilizing diaryliodonium salts under relatively mild conditions have been disclosed.…”