123 CH2-CCH2CI CH3 2-甲基-3-氯丙烯 7654 321 H;C-CH-CH-CH2-CH-CH-CH3 CH CI CH3 2,6-二甲基-3-氯-5-碘庚烷H3 C CH CH CH2 CH CH CH3 I Cl CH3 CH3 7 6 5 4 3 2 1 2，6-二甲基-3-氯-5-碘庚烷 CH2 =CCH2 Cl CH3 1 2 3 2-甲基-3-氯丙烯