3、成环: (1)、三(四)元环: CICH2~ .coocHs OH H2 COOCHs H2 3员: CH2N2 R-f9R生 R 4员: OEt COOEt Br(CH2)3Br CH2(COOEt )2 COOEt COOH 水解☐」 酸化,-C02 Organic ChemOrganic Chem 3、成环: (1)、三(四)元环: 3员: 4员: ClCH2 C H2 H2 C COOCH3 OH COOCH3 C H C H R R' CH2 N2 R R' Br(CH2 ) 3Br + CH2(COOEt)2 COOEt COOEt 水解 酸化,-CO2 COOH OEt