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Lewis Acid Catalyzed Benzylic Bromination
Author(s) -
Shibatomi Kazutaka,
Zhang Yanhua,
Yamamoto Hisashi
Publication year - 2008
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.200800087
Subject(s) - halogenation , lewis acids and bases , chemistry , catalysis , organic chemistry , reagent , yield (engineering) , zirconium , chloride , brønsted–lowry acid–base theory , medicinal chemistry , materials science , metallurgy
The Lewis acid catalyzed bromination of aromatic side chains was achieved efficiently by using 1,3‐dibromo‐5,5‐dimethylhydantoin (DBDMH) as the bromination reagent under mild conditions. Zirconium(IV) chloride showed the highest catalytic activity for this benzylic bromination. It was revealed that the present Lewis acid catalysis proceeds by the radical‐generation pathway. In contrast, Brønsted acids promoted aromatic‐ring bromination without any benzylic bromination. Monobromination of tetramethylsilane was also demonstrated with zirconium(IV) chloride and DBDMH to provide the desired product in good yield.