(1) CH3-CH-CH Br,CH,一CH-CH(主要) CH3 -CH=CH (2 CH3CH2-CH2 Br→CH一C-CH(次要） B 正碳离子 sp2杂化 (CH3)3C (CH3)CH CH3CH2 CH; 3 29 19 稳定性：3°>2°>1°>CH CH3 CH CH2 H + (1) (2) (2) CH3 CH2 CH2 + 稳定性？ (CH3) 3 C + (CH3) 2 CH + CH3 CH2 + CH3 + 3° 2° 1° C + 正碳离子 Br￾CH3 CH CH3 Br (主要) Br￾CH3 CH2 CH2 Br (次要) CH3 CH CH3 (1) + 稳定性：3°> 2°> 1°> CH3 + sp2 杂化