α, β-Unsaturated esters were made to react with N, N-dibromobenzenesulfonamide and formic acid in chloroform to give bromo-formyloxyesters. Methyl acrylate (1a), ethyl crotonate (2a), ethyl trans-cinnamate (3a), methyl tiglate (4a), methyl methacrylate (5a), and methyl phenylacrylate (6a) gave methyl 2-bromo-3-formyloxypropionate (1b), ethyl erythro-2-bromo-3-formyloxybutyrate (2b), ethyl erythro-2-bromo-3-formyloxy-3-phenylpropionate (3b), methyl erythro-2-bromo-3-formyloxy-2-methylbutyrate (4b), a mixture of methyl 3-bromo-2-formyloxy-2-methylpropionate (5b) and methyl 2-bromo-3-formyloxy-2-methylpropionate (5c), and methyl 3-bromo-2-formyloxy-2-phenylpropionate (6b) respectively in good yields.
Comparative study of the vicinal functionalization of olefins with 2:1 bromide/bromate and iodide/iodate reagents
作者:Manoj K. Agrawal、Subbarayappa Adimurthy、Bishwajit Ganguly、Pushpito K. Ghosh
DOI:10.1016/j.tet.2009.01.095
日期:2009.4
halohydrins, halo methyl ethers, and halo acetates from olefins using 2:1 Br−/BrO3− and I−/IO3− reagents. In many cases both reagents afforded products selectively in high yields. The highest halogen atom efficiencies attained were 97% and 93% for Br−/BrO3− and I−/IO3−, respectively. Of the two reagents, I−/IO3− was established to be the preferred reagent for vicinal functionalization of linear alkenes and
Dimethylformamide (DMF) is shown to react in a stereospecific, regioselective fashion with bromonium, or α-bromocarbonium ions, generated from a variety of olefins and N-bromosuccinimide (NBS) in the presence of water. The bromoformate is often accompanied by dibromide and bromohydrin; at least some of the latter arising from hydrolysis of the bromoformate. Although alkyl and aryl migration is not observed, rearrangement
Regio- and stereoselective hydroxybromination and dibromination of olefins using ammonium bromide and oxone®
作者:Arun Kumar Macharla、Rohitha Chozhiyath Nappunni、Narender Nama
DOI:10.1016/j.tetlet.2012.01.026
日期:2012.3
synthesis of vicinal bromohydrins and dibromides fromolefins is presented. Various olefins are regio- and stereoselectively hydroxybrominated and dibrominated with anti fashion, following Markonikov’s rule, using eco-friendly, non-toxic, and stable reagents such as NH4Br and oxone® in CH3CN/H2O (1:1) and CH3CN without employing catalyst in moderate to excellent yields. Bromohydrins are formed instantaneously
Amphiphilic Indoles as Efficient Phase‐Transfer Catalysts for Bromination in Water
作者:Qingyu Zhang、Yongyuan Xu、Xiaochen Liang、Zhihai Ke
DOI:10.1002/cssc.202200574
日期:2022.6.22
Just add water: Under the phase-transfer catalysis of amphiphilic indoles, an efficient and environmentally friendly bromination in water is developed. As test reactions, hydroxybromination of olefins and aromatic bromination are conducted.