影响E2反应区域选择性的因素 1) Base structure(碱的结构) CH CH 3 CH3 CH2CH-CCH2 Ro--Ch3C=CCH CH3 CHC=CH2 CH2 Br CH 3 CH 3 Ba More substituted Less substituted ase product product CH2CH,O 79% (CH3)3C0 27 CH3CH2(CH3)2CO 19% 1% (CH)3CO 8% 碱的体积增大,多取代产物减少匚影响E2反应区域选择性的因素： 1) Base Structure（碱的结构） Br CH3 CH3 CH3 CH3 CH3 CH3 + RO - CH3C=CCH3 Base + More substituted product Less substituted product CH3CH2O - (CH3)3CO - CH3CH2(CH3)2CO - 19% 81% (CH3CH2)3CO - 8% 92% 79% 21% 27% 73% CH3CH-CCH3 CH3CHC=CH2 碱的体积增大，多取代产物减少