Sol-Gel Entrapped Pyridinium Hydrobromide Perbromide as a Recyclable Bromination Agent: Its Application to a One-Pot Bromination and Dehydrobromination Process
作者:Yevgenia Levin、Khalil Hamza、Raed Abu-Reziq、Jochanan Blum
DOI:10.1002/ejoc.200500982
日期:2006.3
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
硅胶溶胶-凝胶包裹的过溴化氢溴化吡啶鎓可用于清洁、无味地溴化各种底物,包括烯烃、酮和芳烃。用过的杂化溴化试剂可重新充入溴并循环使用。在溶胶-凝胶包埋的 1,5,7-三氮杂双环 [4.4.0]dec-5-ene 存在下,二溴化物脱溴化氢得到乙烯基单溴化物和/或炔烃。将吡啶鎓衍生物和胍碱封装在单独的溶胶-凝胶基质中,可以在一锅反应中使用两种相反的试剂,而不会相互破坏。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)