0 RCH2CCHCOOC2H5 C2H5O R 0 RCH2C-CCO0C2H5≤→ RCH2C=CCOOC2H5]C2H50H R 0 RCH2CCHCOOC2H5 R O CH3 2 CH3CH2CHCOOC2Hs 1)(C6H5)3CNa CH3CH2CH-C-C-COOC2Hs CH3 2)H CH3 CH2CH3RCH2CCHCOOC2H5 + C2H5O - O R [RCH2C-CCOOC2H5 O R - RCH2C=CCOOC2H5] + C2H5OH O - H + R RCH2CCHCOOC2H5 O R 2 CH3CH2CHCOOC2H5 CH3 1) (C6H5 ) 3CNa 2) H + CH3CH2CH C C COOC2H5 O CH3 CH3 CH2CH3