A Simple and Improved Procedure for the Conversion of Alkynes to 1,2-Diketones by Indirect Electrooxidation With Ruthenium Tetroxide as a Mediator

Article abstract of DOI:10.1055/s-1987-27950

Indirect electrooxidation of alkynes 1 using ruthenium tetroxide as a mediator, leading to 1,2-diones 2 in 72-87percent, is described.The electrolysis is carried out in the presence of a catalytic amount of ruthenium dioxide dihydrate in a two phase system of saturated aqueous sodium chloride and carbon tetrachloride.The overoxidation of 1,2-diones to the corresponding carboxylic acid, an unavoidable drawback generally encountered in the metal oxidation of acetylenes, is suppressed greatly by maintaining the pH of the aqueous phase at 4 and conducting the reaction at 0-5 deg C.The synthetic utility of this electrochemical oxidation is exemplified by the preparation of 2i (82percent), a key intermediate for the synthesis of furaneol 4, from the commercially available 1i.