Mild and Efficient Vicinal Dibromination of Olefins Mediated by Aqueous Ammonium Fluoride
作者:Tony Shing、Ying-Yeung Yeung、Wing Ng
DOI:10.1055/s-0036-1588506
日期:2018.3
A mild and efficient vicinal dibromination of olefins has been developed by using saturated aqueous ammonium fluoride solution as the promoter. Inexpensive and commercially available N -bromosuccinimide (NBS) was used as the brominating reagent. The corresponding vicinal dibromoalkanes could be obtained in good to excellent yields.
A Photoirradiative Phase-Vanishing Method: Efficient Generation of HBr from Alkanes and Molecular Bromine and Its Use for Subsequent Radical Addition to Terminal Alkenes
phase-vanishing (PV) system comprised of an alkane, perfluorohexanes, and bromine was successfully combined by photoirradiation to efficiently generate hydrogenbromide, which underwent radicaladdition with 1-alkenes in the hydrocarbon layer to afford terminal bromides in high yields.
The oxidativebromination of arenes was induced by a vanadium catalyst in the presence of a bromide salt and a Brønsted acid or a Lewis acid under molecular oxygen, which provides an eco-friendly bromination method as compared with a conventional bromination one with bromine. This catalytic reaction could be applied to the bromination of alkenes and alkynes to give the corresponding vic-bromides. Use
芳烃的氧化溴化反应是在分子氧下,在溴化物盐和布朗斯台德酸或路易斯酸存在下,由钒催化剂诱导的,与传统的溴化溴化方法相比,该方法提供了一种环保的溴化方法。这种催化反应可以适用于烯烃和炔烃的溴化,得到相应的VIC -溴化物。已证明使用卤化铝代替布朗斯台德酸作为路易斯酸可为氧化溴化提供更实用的方法。从酮中获得α-溴化产物。发现AlBr 3既是溴化物源又是路易斯酸,可以顺利地诱导溴化。511 H NMR实验表明,这种催化溴化反应可能取决于分子氧下钒催化剂的氧化还原循环。
Debrominations of <i>vic</i>-Dibromides with Diorganotellurides. 1. Stereoselectivity, Relative Rates, and Mechanistic Implications
作者:Timothy S. Butcher、Feng Zhou、Michael R. Detty
DOI:10.1021/jo9713363
日期:1998.1.1
Debrominations of vic-dibromides with diaryl tellurides 1-4 and di-n-hexyl telluride (9) are described. A mechanistic explanation of the debromination is offered which accounts for several key experimental observations: (1) the reaction is highly stereoselective with erythro-dibromides giving trans-olefins and threo-dibromides giving cis-olefins, (2) the reaction is accelerated by more electron-rich