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Mild and Regioselective Bromination of Phenols with TMSBr
Author(s) -
Ma Xiantao,
Yu Jing,
Jiang Mengyuan,
Wang Mengyu,
Tang Lin,
Wei Mengmeng,
Zhou Qiuju
Publication year - 2019
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201900794
Subject(s) - thioether , regioselectivity , chemistry , halogenation , phenols , steric effects , organic chemistry , electrophile , phenol , ketone , amide , aldehyde , medicinal chemistry , catalysis
In this work, an unexpected promoting effect of by‐product thioether was observed, leading to a mild and regioselective bromination of phenols with TMSBr. This method can tolerate a series of functional groups such as the reactive methoxyl, amide, fluoro, chloro, bromo, aldehyde, ketone and ester groups, and has the potential to recycle the by‐product thioether and isolate the desired product under column chromatography‐free conditions. Mechanism studies revealed that O–H ··· S hydrogen bond may be formed between phenol and by‐product thioether. Possibly owing to the steric hindrance effect from by‐product thioether, the electrophilic bromination at para ‐position of phenols is much favorable.