作者:Gregorio Asensio、Gloria Castellano、Rossella Mello、M. E. González Núñez
DOI:10.1021/jo9604189
日期:1996.1.1
The oxidation of lineal, cyclic, and bicyclic aliphatic p-chlorobenzoic and p-chorobenzenesulfonic acid esters 2 with methyl(trifluoromethyl)dioxirane (TFDO) (1) occurs at positions in the hydrocarbon chain distant from the directing group with a significant degree of selectivity to give the corresponding keto or hydroxy esters. Compounds 2 are relatively deactivated with respect to this oxidation due to the electron-withdrawing nature of the ester moiety. Methylene C-alpha-H and C-beta-H bonds remain unchanged in all cases, but tertiary C-beta-H bonds undergo oxidation with TFDO (1). Stereoelectronic factors are used to explain the faster reaction rate in competition experiments for the oxidation of endo-norbornyl ester 2h than for its exo-isomer 2g.