0 0 0 00 +HcOc|5-(0H|5 c-H+ C2h5OH ③交错的酯缩合反应: 例1 H-C-OEt +CH? CH2CO0Et (1)NaOEt H-C-CHCOoEt 甲酸酯,孢-H (2)H CH 00 15 2: Eto-C--C-OEt +CH, CH, COOEt (1) NaOEt CH CHcOOEt 草酸酯,孢-H (2)H C=0 CO CooT CH2 CH (COOEt) 2O NaH O -C-H O + C2 H5 OH O -CH OC2 H5 O - + H-C-OC2 H5 O ③ 交错的酯缩合反应： 例1： H-C-OEt O + CH3 CH2 COOEt (1) NaOEt (2) H+ O H-C-CHCOOEt CH3 甲酸酯，无 -H  (1) NaOEt (2) H+ EtO-C--C-OEt + CH3 CH2 COOEt O O CH3 CHCOOEt COOEt C=O -CO  CH3 CH(COOEt)2 草酸酯，无 -H  例2：