this study, the radical cyclization reactions of cyclic 1,3-dicarbonylcompounds (1a–c) and α,β-unsaturated alcohols (2a–d) through Mn(OAc)3 were performed. A series of biologically interesting dihydropyrans (3–5) and dihydrofurans (6–18) were synthesized as a result of these reactions. Spiro compounds (19–20) were obtained from the reactions of 1,3-dicarbonylcompounds and (E)-2,4-diphenyl-but-3-en-2-ol