Intramolecular Homolytic Displacements. 25. Efficient Access to Epoxides via Induced Decomposition of Unsaturated Peroxyketals Prepared by Addition of a Hydroperoxide to 2-Methoxypropene
作者:Fabienne Ramon、Marie Degueil-Castaing、Bernard Maillard
DOI:10.1021/jo951783n
日期:1996.1.1
The synthetic potential of homolytically induced decompositions of peroxyketals possessing a 1-methoxy-1-methylethoxy fragment, as a means of access to epoxides, was demonstrated. The propagation step of this free radical reaction proceeds via (i) the addition of a carbon-centered radical to the double bond followed by an S(H)i reaction on the peroxidic bond with the generation of a 1-methoxy-1-methylethoxy radical, (ii) formation of a methyl radical from the latter by beta-elimination, and (iii) regeneration of the carbon-centered-radical via iodine atom abstraction by the methyl radical from an alkyl iodide. These reactions afforded various functionalized epoxides in good yields.