Reactions of diphenylketene and methylphenylketene with some cis-cyclohexa-3,5-diene-1,2-diol derivatives

Abstract

The reaction of the dienes 1–5 with diphenylketene to give the [2 + 2]-adducts 6–10 and the [4 + 2]-adducts 11–15, respectively, has been found to occur by an ionic mechanism involving the zwitterion 16. The reactions of the dienes 2 and 3 with methylphenylketene (and also cyclohexa-1,3-diene with diphenylketene) proceed in a similar fashion. The enol ether 13 was converted into the polyoxygenated cyclohexane derivatives 33, 35 and 38.