ALLYLIC CARBOXYLATIONS AND LACTONIZATION USING BENZOQUINONE AND HYDROGEN-PEROXIDE OR TERT-BUTYL HYDROPEROXIDE AS OXIDANTS

Two new systems have been developed for catalytic carboxylation of alk enes. Both use palladium-(II) as catalyst and benzoquinone as cocataly st. In the first hydrogen peroxide was used as oxidant in acetic acid solution. Alkenes such as cyclohexene and 5-decene were converted clea nly to allylic acetates, but with 1-decene mainly the methyl ketone wa s formed. A diene such as 1,3-cyclohexadiene gave the diacetate while cis-1,2-divinylcyclohexane gave the cyclized monoacetate. In the secon d system, tert-butyl hydroperoxide was used as oxidant, permitting a w ider choice of solvents and nucleophiles. Intramolecular reaction to l actones was possible in addition to allylic addition of acids such as benzoic, pivalic, and (S)-O-acetylmandelic acid.