1-Chloro-1-fluorocyclopropanes [I; R, R1, R2, R3 = H, OMe, Me, Me; Me, OMe, H, H; H, OMe, Me, Me2CH(CH2)3; H, OMe, Me, Me2C:CHCH2CH2; Me, Me, H, MeOCH:CMeCH2CH2; H, OEt, H, Me] were easily prepd. by cycloaddn. of ClFC: to alkenyl ethers in a 2-phase system. I were solvolyzed by heating in an aq. solvent mixt. to give 2-fluoro-2-alkenals, which were readily reduced by LiAlH4 to the corresponding 2-fluoro-2-alkenols. [on SciFinder (R)]