Fluorinated derivatives of 3-alkylidene-2(3H)-dihydrofuranone have been synthesized by sodium dithionite initiated tandem perfluoroalkylation-cyclization of allylic 2-alkynoates in fair to good yield and high stereoselectivity. Fluorinated 3-alkylidene-2(3H)-pyrrolidone derivatives were prepared similarly. A mechanistic rationale concerning the different radical steps and the differences between esters and amides was given.