Dimethyl Sulfoxide Participating in Copper(I) Iodide‐Catalyzed Cascade Oxidation/Formylation Reactions: The Synthesis of α‐Formylpyrroles from 2,3‐Dihydro‐1H‐pyrroles

Abstract

An efficient copper-catalyzed tandem oxidation/a-formylation reaction of 2,3-dihydro-1H-pyrroles in an oxygen atmosphere has been developed. The new reaction is conducted in dimethyl sulfoxide (DMSO), which serves as both the carbonyl carbon source and solvent, in the presence of trifluoroacetic acid to directly generate structurally diverse a-formylpyrrole derivatives in one pot in moderate to good yields. Sensitive aldehyde groups remain intact in the presence of an oxidant, trifluoroacetic acid and a transition metal salt. A possible mechanism is presented.

Photoinduced N‐Methylation and N‐Sulfonylation of Azobenzenes with DMSO Under Mild Reaction Conditions

“…On the other hand, DMSO also can be converted into a lot of useful chemicals . In the past decades, numerous transformations by using DMSO as a versatile reagent have been developed, including methylation of isoquinoline N ‐oxides, and aromatic nitro compounds and amines,, formylation of 1 H ‐pyrroles,, and imidazo[1,2‐a]pyridines, cyanation of indoles at 3‐position, and aryl iodides, methylthiolation of arenes, (hetero)arenes, styrenes and alkynes,, sulfonylation of aryl halides and olefins,, and oxidation of arenes, secondary bromides or olefins, oxidative coupling of styrenes with aldehydes, as oxidant, as well as ligand . Among these protocols, methylation and sulfonylation strategies have received significant attention owing to these groups widely found in the important biological and pharmaceutical compounds .…”

Ni‐Catalyzed Synthesis of Methylenebisamides: Dual Role of DMSO Both as Methylene Source and Oxidant

“…Furthermore, DMSO has some well‐studied medicinal applicartions . However, this compound, due to its stability and relative nonreactivity has limited applications in organic synthesis; and as a result, making use of DMSO as a reagent in synthesis has recently attracted many attentions . In the past few years, DMSO has been employed as a source for embedding ‐Me, ‐CHO, ‐CN, ‐SMe, ‐SO 2 Me, and ‐O in organic structures .…”

Dimethyl Sulfoxide as a Synthon in Organic Chemistry

“…(Scheme 15). 63 The reaction, performed under an oxygen atmosphere, employed catalytic copper(I) iodide and excess trifluoroacetic acid, while they had previously reported an analogous transformation mediated by FeCl 3 . 64 In all, 24 examples were demonstrated including the formation of compounds 106-109.…”