二、E2 Reaction 3. Regiochemistry(区域选择性) 从含氢较少的β-碳上消去得到取代基较多的 烯烃一 Zaitsev's rule OCH CH3CHCH2 CH3 CHrCH=CHCH3 CH=CHCHbCh Br 80% 20% OH CH CHCHCHCH 3 CH3 CH=CHCH, CH3 CH2=CHCH2CH2CH3 Cl 67% 33% CH CH3 CH- CH? CCHCH OH 3 CH3C=CHCH3 CH2=CCH2 CH3 Cl 70% 30二、E2 Reaction 3. Regiochemistry（区域选择性） 从含氢较少的β-碳上消去得到取代基较多的 烯烃 — Zaitsev’s Rule CH3CHCH2CH3 Br - OCH3 + CH3CHCH2CH2CH3 Cl - OH + 80% 20% 67% 33% CH3CCH2CH3 Cl CH3 - OH CH2=CCH2CH3 CH3 CH3C=CHCH3 CH3 + 70% 30% CH3CH=CHCH3 CH2=CHCH2CH3 CH3CH=CHCH2CH3 CH2=CHCH2CH2CH3