An efficient synthesis of spiroannulated dihydrofurans is achieved from 1,3-dicarbonyl compounds and exocyclic alkenes in the presence of cerium ammonium nitrate(IV) in moderate yields. In the case of entries 3-9, as a single product was seen. Especia...
An efficient synthesis of spiroannulated dihydrofurans is achieved from 1,3-dicarbonyl compounds and exocyclic alkenes in the presence of cerium ammonium nitrate(IV) in moderate yields. In the case of entries 3-9, as a single product was seen. Especially, reaction of 15 with methylenecyclohexane afforded the two regioisomeric cyclo adducts 21 and 22. The structures of these adducts were confirmed by IR and NMR-Spectra.