Dienols, oxygen addition

EPR in conjuction with the spin trapping technique has provided evidence for the intermediacy of free radicals in the formation of an endoperoxide by spontaneous addition of oxygen on a dienol it has been suggested that a long-lived triplet biradical intermediate is formed by addition of 302 to dienol.232 A probable mechanism (Scheme 10) has been postulated for the formation of 1,2-dioxane and acetophenone in the reaction of an alkene with Co(II)-02-Et3SiH.233... 

Lead tetra-acetate oxidation of the allylic alcohols (170)—(172) and (182) leads to the formation of the epoxides (183)—(186), products of a novel internal addition reaction of the electron-deficient alcohol oxygen to the allylic double bond. In some cases, (171) and (172), the formation of a new type of acetoxylated enol ether (173) and (174) is observed. Oxidation of the allylic dienols (175) and (176) gives the epoxyacetates (187) and (188). A variety of cyclization products was also isolated. Their formation requires an isomerization of the allylic trans double bond to cis.69 Lead tetra-acetate oxidation of dihydro-y-ionol (189) gives the new bicyclic ether... 

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