CH2:CFCMe:CHR (I, R = cyano, SO2Ph) were prepd. by ring cleavage of the cyclopropanes II (R = cyano, SO2Ph), prepd. by treating methallyl chloride with FCHCl3 and substitution in I (R = Cl). I (R = Bu, Ph) and Me3CCH:CHCMe:CF(CH2)4Me were obtained by treating II (R = P+Ph3I-) with Me3CCHO and BuLi. I (R = H) formed an adduct with maleic anhydride. Bromination of I (R = H) at room temp. gave E- and Z-BrCH2CF:CMeCH2Br, CH2:CFCMeBrCH2Br, and CH2:CMeCBrFCH2Br. When I (R = H) was treated with Br-HOAc, CH2:CFCMe(OAc)CH2Br and CH2:CMeCF(OAc)CH2Br were obtained. [on SciFinder (R)]