0 0 0 00 +H6-oc州a,HcH一→0-H+c0H ③交错的酯缩合反应： 0 例1： H-C-OEt CH2CH2COOEt (1)NaoEt H-C-CHCOOEt 甲酸酯，孢H (2)H CH3 00 例2： EtO-C-C-OEt+CH CH2COOEt(1)NaoEt CH3CHCOOEt 草酸酯，H (2) C=0 COOEt CH CH (COOEE)O 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：