Methylene-Tethered Arylsulfonation and Benzotriazolation of Aryl/Heteroaryl C–H Bonds with DMSO as a One-Carbon Surrogate

Abstract

The Selectfluor-mediated approach toward the synthesis of methylene-tethered arylsulfonation and benzotriazolation of imidazopyridines has been described. The reaction involves imidazopyridine, aryl sulfinate, or benzotriazole and dimethyl sulfoxide (DMSO) in the presence of Selectfluor, where DMSO acts as a one-carbon synthon. The protocol has been extended to the methylene-tethered arylsulfonation and benzotriazolation of β-naphthols. The mechanistic insights show that the intermediate 3-((methylthio)­methyl)-2-phenylimidazo­[1,2-a]­pyridine is generated from imidazopyridine, DMSO, and Selectfluor. The nucleophilic displacement by the aryl sulfinate salt or benzotriazole on the intermediate afforded the product.

Synthesis of Substituted Pyrimido[1,2‐b]indazoles through (3+2+1) Cyclization of 3‐Aminoindazoles, Ketones, and N,N‐Dimethylaminoethanol as One‐Carbon Synthon

“…The product yield was dramatically decreased at lower reaction temperatures (entries [17][18]. Furthermore, decreasing the amount of catalyst from 20 mol% until 1 mol% had significant influence on the product yield (entries [19][20][21]. Based on the above results, the optimal reaction conditions were set up as shown in Table 1, entry 5.…”

Selectfluor Mediated Regioselective Annulation Using Imidazopyridines, Acetophenones and DMF as Carbon Synthon

“…In the initial experiment, reaction between 1 a and 2 a using Selectfluor as an oxidant in DMSO at 120 °C afforded exclusively 5 in 75% yield (Table 1, entry 1). The methylene in 5 has been derived from DMSO [4e] . The source of C1 synthon in 5 using H 2 O 2 /DMSO system has been reported from DMSO [15a] .…”

Synthesis and site selective C–H functionalization of imidazo-[1,2-a]pyridines

“…They found that the reaction proceeds through an ionic mechanism via the involvement of a 3-((methylthio)methyl)-2-phenylimidazo[1,2- a ]pyridine intermediate (Scheme 32). 83…”

“…They found that the reaction proceeds through an ionic mechanism via the involvement of a 3-((methylthio)methyl)-2-phenylimidazo[1,2-a]pyridine intermediate (Scheme 32). 83 Recently, the Singh group published a novel and extremely effective method for the heteroarylation of overfilled bromoamides 84 by electrophilic substitution of aromatic imidazoheterocycles 85 and indolizines under moderate reaction conditions (room temperature, metal and oxidant free). This transition is distinguished by the presence of an in situ produced aza-oxyallyl cation as an alkylating agent.…”