YDifluoromethyl-a-methylene-y-butyrolactone 2 was readily prepared from the Reformatsky-type reaction of difluoroacetaldehyde ethyl hemiacetal 1 and methyl 2-(bromomethyl)acrylate in Zn-THF system, and +fluoromethyl-a-methylene-~butyrolactams 6 were also prepared from difluoroethanimine. yDifluoromethyl-a-methylene-y-butyrolactone 2 was found to possess comparable or even stronger in vitro antitumoral activity than the currently used B-fluorouracil.