Selective oxidation of acetylenic 1,4-diols with Dioxiranes in comparison with the Methyltrioxorhenium-Hydrogen Peroxide oxidant

Dimethyldioxirane and its trifluoro analog were employed to achieve selectively the direct transformation of hex-3-yne-2,5-diol and 1,4-diphenyl-2-butyne-1,4-diol into carbonyls, e.g., I (R = Me, Ph), leaving the carbon-carbon triple bond moiety untouched. The results were compared with those recorded in the analogous oxidn. using the methyltrioxorhenium/H2O2 homogeneous system. The powerful methyl(trifluoromethyl)dioxirane was the reagent of choice to achieve optimum yields of the target alkyne-1,4-diones, which were extremely versatile synthons.