Cope Rearrangement of 1-Acyl-2-vinylcyclopropanes to Cyclohept-4-Enones.

Cycloheptenones are widespread in natural products and bioactive molecules. An efficient and convenient NaH-mediated Cope Rearrangement of doubly activated vinylcyclopropanes is reported for the synthesis of cyclohepten-4-ones. These flexible intramolecular reactions were applicable to a wide range of substrates and could be performed on gram scale.