COOC2Hs C2HsONa COOC2Hs COOC2H5 -CH CH3CH2Br CH3CH2CH C2H5 COOC2Hs COOC2Hs COOC2Hs COOH 1)C2HsONa 1)OⅢ -CO2 CH;CH2CHCOOH 2)CH3I chcme ccncma cno COOC2Hs COOH CH3 2 CH2(COOC2H5)2 CHONa2CH(COOCH BrCH2CH2Br CH2CHCO0C2Hs)21)OH、△ CH2CH2COOH CH2CH(COOC2Hs)2 2)H 之-C02CH2CH2C00H CH2 COOC2H5 COOC2H5 C2H5ONa CH COOC2H5 COOC2H5 _ CH3CH2Br CH3CH2CH COOC2H5 COOC2H5 1) C2H5ONa 2) CH3 I CH3CH2C CH3 COOC2H5 COOC2H5 1) OH - 2) H + CH3CH2CCH3 COOH COOH -CO2 CH3CH2CHCOOH CH3 2 CH2(COOC2H5) 2 C2H5ONa 2 CH(COOC2H5) 2 _ BrCH2CH2Br CH2CH(COOC2H5) 2 CH2CH(COOC2H5 ) 2 CH2CH2COOH CH2CH2COOH 1) OH - 2) H + -CO2