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Sol‐Gel Entrapped Pyridinium Hydrobromide Perbromide as a Recyclable Bromination Agent: Its Application to a One‐Pot Bromination and Dehydrobromination Process
Author(s) -
Levin Yevgenia,
Hamza Khalil,
AbuReziq Raed,
Blum Jochanan
Publication year - 2006
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.200500982
Subject(s) - hydrobromide , halogenation , chemistry , pyridinium , reagent , silica gel , organic chemistry , guanidine , bromine , polymer chemistry
Silica sol‐gel encaged pyridinium hydrobromide perbromide can be used for clean, odorless bromination of a variety of substrates, including alkenes, ketones, and arenes. The used heterogenized bromination reagent can be recharged with bromine and recycled. In the presence of sol‐gel entrapped 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene, dibromides are dehydrobrominated to give vinyl monobromides and/or alkynes. Encapsulation of the pyridinium derivative and the guanidine base within separate sol‐gel matrices enables the use of both opposing reagents in one‐pot reactions without their mutual destroying each other. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)