20. 3 The acetoacetic ester synthesis: Synthesis of substituted acetones R—X CH CH2tR or CH3 cH—R R—X CH CCH,COOCH,CH20.3 The Acetoacetic ester synthesis: Synthesis of substituted acetones CH3 O CH2 R or CH3 O CH R R CH3CCH2COOCH2CH3 O R X R X