Effect of solvent and temperature upon the rotationally averaged vicinal coupling constants of some substituted 1,2-dibromoethanes
作者:W. F. Reynolds、D. J. Wood
DOI:10.1139/v69-215
日期:1969.4.15
The solvent dependence of vicinalcouplingconstants has been investigated for (1,2-dibromoethyl)-benzene and three of its 4-substituted derivatives and for threo- and erythro(1,2-dibromopropyl)benzene. The temperature dependence of the vicinalcouplingconstants of three of the compounds has also been investigated. The difference between the two vicinalcouplingconstants of (1,2-dibromoethyl)benzene
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.
The α-halogenation of α,β-unsaturated carbonyls and dihalogenation of alkenes using bisacetoxyiodobenzene/pyridine hydrohalides
作者:Marsewi Ngatimin、Christopher J. Gartshore、Jeremy P. Kindler、Sudha Naidu、David W. Lupton
DOI:10.1016/j.tetlet.2009.08.038
日期:2009.11
A procedure for the α-chlorination or bromination of a number of α,β-unsaturated carbonyls, and the dichlorination or bromination of alkenes, is developed using bisacetoxyiodobenzene (BAIB) and the HCl or HBr salt of pyridine. The reaction proceeds in an acceptable to a good yield and has a broad substrate scope. The dibromination is also achieved using a chiral I[V] reagent, although little enantioselectivity
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
We report herein a regio‐ and stereoselective photocatalytic hydrogenolysis of allylicalcohols to form unsaturated hydrocarbons employing a palladium(II)‐loaded titanium oxide; the reaction proceeds at room temperature under light irradiation without stoichiometric generation of salt wastes. Olefin and saturated alcohol moieties tolerated the reaction conditions. Hydrogen atoms were selectively incorporated