Combination of NH2OH·HCl and NaIO4: an effective reagent for molecular iodine-free regioselective 1,2-difunctionalization of olefins and easy access of terminal acetals
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
The ringopening of epoxides with elementaliodine and bromine in the presence of three pyridine-containing macrocyclic diamides as new catalysts affords vicinal iodo alcohols and bromo alcohols in high yields. This new procedure occurs regioselectively under mild conditions in various aprotic solvents. The catalysts are easily recovered and can be reused several times.
ABSTRACT A simple, efficient, and environmentally benign protocol for the synthesis of vicinal iodohydrins and iodoesters from olefins using NH4I and Oxone in CH3CN/H2O (1:1) and dimethylformamide (DMF) / dimethylacetamide (DMA), respectively, without employing a catalyst at room temperature is described. Regio- and stereoselective iodohydroxylation and iodoesterification of various olefins with anti fashion
Aerobic Oxidation of Alkenes to Esters of Vicinal Diols with a<i>syn</i>-Configuration Catalyzed by I<sub>2</sub>and the H<sub>5</sub>PV<sub>2</sub>Mo<sub>10</sub>O<sub>40</sub>Polyoxometalate
作者:Ronny Neumann、Olena Branytska
DOI:10.1055/s-2005-917069
日期:——
A new method for the synthesis of vicinal diols fromalkenes has been developed. Reaction of molecular iodine in the presence of a polyoxometalate as oxidation catalyst under aerobic conditions in acetic acid solvent leads to the oxidative iodoacetoxylation of an alkene, i.e. formation of a 1,2-iodoacetate. Further in situ substitution of the iodide by water yields the 1,2-diol monoacetate with a predominantly