The reactions of cyclohexa-2,4-dienones with cyclopentadiene

Abstract

The reactions of cyclopentadiene with cyclohexa-2,4-dienones of general structure (VII) have been shown to proceed by initial diene addition of the hydrocarbon to the 4,5-double bond of the cyclohexadienone. The resulting adducts, which are derivatives of tricyclo[6,2,1,0]undeca-5,9-dien-4-one (III), rearrange even at room temperature to give products having the tricyclo[5,2,2,0]undeca-4,10-dien-8-one skeleton (I), but their intermediacy has been demonstrated by trapping experiments with phenyl azide.