Oxidation‐Induced para‐Selective Formylation of N,N‐Substituted Aniline

Abstract

Selective formylation of aromatic C−H bonds is of great importance, since aromatic aldehydes are valuable synthetic intermediates in organic chemistry. Recently, an impressive progress has been made in this field. However, an effective strategy for the selective formylation of N,N‐substituted anilines is still needed. In this regard, we disclose a novel oxidant‐induced para‐selective formylation of N,N‐substituted aniline towards the synthesis of aromatic aldehydes in this work. Using DDQ as the sole oxidant, various N,N‐substituted anilines could be transformed into the desired formylation products under metal‐free conditions, and the yield is up to 92 %.

A stable and recyclable Z-scheme g-C3N4/rGO/BiVO4 heterojunction photocatalyst for site-selective C-3 formylation of indoles with methanol as a formyl source under visible light

“…To overcome these shortcomings, various alternative formylating reagents were developed for the C-3 formylation of indoles under photochemical, electrochemical and thermochemical conditions. The first type was amines, such as N , N -dimethylaminoethanol, 8 N -methylaniline, 9 N , N -dimethylaniline, 10 tetramethylethylenediamine (TMEDA), 11 hexamethylenetetramine (HMTA) 12 and trimethylamine 13 (Scheme 1b). The second type was carbonyl compounds, for instance, glyoxylic acid, 14 HCOOH, 15 HCHO (aq.)…”