Electron-rich and electron-poor alkenes have been dibrominated using a rapid and sustainable procedure. The reactions were conducted in aqueous medium and basic ionic liquids which catalyzed the direct addition of bromine. The protocol leads to remarkable results, high yields under mild conditions, complete chemo- and stereo-selectivity and allows the recycling of ionic liquids, reducing costs, and
The photobromination of CHbonds by using molecular bromine was reinvestigated under microfluidic conditions. The continuous‐flow method suppressed the production of dibrominated compounds and effectively produced the desired monobrominated products with high selectivity. Rapid bromination of benzylic substrates containing a photoaffinity azide group was achieved without any decomposition.
A Highly Efficient Method for the Bromination of Alkenes, Alkynes and Ketones Using Dimethyl Sulfoxide and Oxalyl Bromide
作者:Hongyu Tian、Baoguo Sun、Rui Ding、Jiaqi Li、Wenyi Jiao、Mengru Han、Yongguo Liu
DOI:10.1055/s-0037-1609560
日期:2018.11
α-bromoketones. The pairing of DMSO and oxalyl bromide is reported as a highlyefficient brominating reagent for various alkenes, alkynes and ketones. This bromination approach demonstrates remarkable advantages, such as mild conditions, low cost, short reaction times, provides excellent yields in most cases and represents a very attractive alternative for the preparation of dibromides and α-bromoketones.
Selective Conversion of Epoxides to<i>vic</i>-Halo Alcohols and Symmetrical or Unsymmetrical Dihalides by Triphenylphosphine/2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in the Presence of Quaternary Ammonium Halides
A new method is described for the efficient and selective conversion of epoxides to vic-halo alcohols or symmetrical and unsymmetrical dihalides using PPh 3 /DDQ/F 4 NX (X = Cl, Br, I) as a mixed-reagent system.