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Sequential Continuous‐Flow Synthesis of 3‐Aryl Benzofuranones
Author(s) -
Xin HaiLong,
Rao Xiaofeng,
Ishitani Haruro,
Kobayashi Shū
Publication year - 2021
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.202100461
Subject(s) - glyoxylic acid , chemistry , aryl , catalysis , yield (engineering) , continuous flow , organic chemistry , alkylation , benzofuran , materials science , alkyl , physics , mechanics , metallurgy
A sequential continuous‐flow system to produce 3‐aryl benzofuranones was developed. Starting from 2,4‐di‐ tert ‐butylphenol and glyoxylic acid monohydrate, both the initial cyclocondensation and the subsequent Friedel−Crafts alkylation were catalyzed by the same heterogeneous catalyst, Amberlyst‐15H. The catalyst has a promising life‐time for these two steps, and it was able to be recovered and reused for several runs without deactivation. By using the established flow system, 5,7‐di‐tert‐butyl‐3‐(3,4‐dimethylphenyl)‐3H‐benzofuran‐2‐one (Irganox HP‐136), which is a commercial antioxidant, was prepared in 88% two‐step yield. Reactions with various aromatic compounds proceeded well under flow conditions to afford 3‐aryl benzo‐furanone derivatives in high yields with good functional group compatibility.