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Please login to access the full content or check if you have access via Variation 1: Hydrolysis of α-Oxo Ketals

DOI: 10.1055/sos-SD-026-00532

Landais, Y.; Vincent, J. M.Science of Synthesis, (200526667.

Hydrolysis of α-oxo ketals under mild, acidic conditions is a general method that provides the desired 1,2-diketones in consistently high yield. Acids such as formic acid (e.g., conversion of 93 into 94, Scheme 26),[‌64‌] hydrochloric acid,[‌65‌,‌66‌] and 4-toluenesulfonic acid[‌67‌,‌68‌] are typically employed, either in water or in a mixture of water and acetone, tetrahydrofuran, or methanol. The hydrolysis proceeds at room temperature or under reflux. These conditions are compatible with most functional groups as illustrated in Scheme 26. Mixed α-oxo ketals 96 are prepared in one step through coupling of 1,2-diethoxy-1,2-bis(trimethylsiloxy)ethene (95) with an acyl chloride under Lewis acid catalysis.[‌65‌] Mild hydrolysis of 96 then leads to 1,2-diketones 97 in high yield. An example of the use of hydrochloric acid is shown for the formation of 1,2-diketone 99 from dimethyl acetal 98.[‌66‌]

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