Selective oxidation of acetylenic 1,4-diols with dioxiranes in comparison with the methyltrioxorhenium-hydrogen peroxide oxidant

Abstract

Dimethyldioxirane (DMD) and its trifluoro analog (TFD) were employed to achieve selectively the direct transformation of diol 3a and of diol 3b into the corresponding carbonyls. The results are compared with oxidations using methyltrioxorhenium (MTO)/85% H2O2. Dimethyldioxirane (1a) and its trifluoro analog (1b) were employed to achieve selectively the direct transformation of hex-3-yne-2,5-diol 3a and 1,4-diphenyl-but-2yne-1,4-diol 3b (two representative acetylenic 1,4-diols) into the corresponding carbonyls, leaving the carbon-carbon triple bond moiety untouched. The results are compared with those recorded in the analogous oxidation using the methyltrioxorhenium (MTO)/85% H2O2 homogeneous system. The powerful methyl(trifluoromethyl)dioxirane (1b) is the reagent of choice to achieve optimum yields of the target alkyne-1,4-diones, which are extremely versatile synthons. © 2004 Elsevier Ltd. All rights reserved.