• With 2-formylcyclohexanones, spirocyclopentenes are obtained: J. Am. Chem. Soc., 99, 7307 (1977). Na carboxylates give 2,3-dihydrofurans: Tetrahedron Lett., 4353 (1975), and thiolcarboxylates give dihydrothiophenes, readily aromatized to thiophenes with DDQ: J. Chem. Soc., Perkin 1, 2403 (1994):
• Valuable intermediate for cycloalkenylation of compounds containing a nucleophilic center and a carbonyl group. Nucleophilic ring-opening of the cyclopropyl ring is followed by intramolecular Wittig reaction (see Appendix 1) of the intermediate carbonyl-phosphorane; e.g., with ?-keto esters, cyclopentenes are formed: J. Am. Chem. Soc., 96, 1607 (1974):