The reaction of 4-hydroperoxy-2,4,6-trimethylcyclohexa-2,5-dienone with acetaldehyde using trimethylsilyl trifluoromethanesulfonate as catalyst gives 1,1′-bis[(1,3,5-trimethyl-4-oxo-2,5-cyclohexadienyl) peroxy]diethyl ether (7) in 70% yield. The structure of this unusual acetal was determined by X-ray analysis.