Hydrolysis of 1,4,6-trioxaspiro[4.5]decanes to .delta.-lactones using 2,3-dichloro-5,6-dicyanobenzoquinone in aqueous acetone

A selective hydrolysis of 1,4,6-trioxaspiro[4.5]decane orthoesters by 2,3-dichloro-5,6-dicyanoquinone (DDQ) in aqueous acetone in the presence of other acid-sensitive ketals is suggested to involve the formation of a charge-transfer complex followed by hydrolysis. A hydride-transfer mechanism for this oxidation was excluded