ESTER EN。 LATES 579 (c) The disconnection approach to retrosynthetic analysis reveals that the preparation of 5-hexen- 2-one by the acetoacetic ester synthesis requires an allylic halide H,C=CHCH,$CH, CCH3 H,C=CHCH, CH,CCH Derived from alkyl halide H_C=CHCH2Br CHaCCHCOCH CH3 2.HO-HO .NaoCHCH3 HC=CHCH, CH, CCH 4. heat Allyl bromide hyl 21.7(b) Nonanoic acid has a CH3(CH,)CH attached to the CH, COH synthon CH,(CH),,+-CH, COH> CH,CH,),CH,X+: CH,COH Required alkyl halide Derived from Therefore the anion of diethyl malonate is alkylated with a l-haloheptane CH3(CH2)5 CH2 Br CH2(COOCHCH3)2- cthanol CH3(CH2)sCH CH(COOCH2CH3) Diethyl malonate Diethyl 2-heptylmalonate CHa(CH2)5CH,CH,CO,H Nonanoic acid (c) Disconnection of the target molecule adjacent to the a carbon reveals the alkyl halide needed to react with the enolate derived from diethyl malonate. CH,CH, CHCH, CH, COH CHCH,CHCH,X CH, COH Back Forward Main Menu TOC Study Guide Toc Student OLC MHHE Website(c) The disconnection approach to retrosynthetic analysis reveals that the preparation of 5-hexen- 2-one by the acetoacetic ester synthesis requires an allylic halide. 21.7 (b) Nonanoic acid has a CH3(CH2)5CH2@ unit attached to the synthon. Therefore the anion of diethyl malonate is alkylated with a 1-haloheptane. (c) Disconnection of the target molecule adjacent to the carbon reveals the alkyl halide needed to react with the enolate derived from diethyl malonate. Derived from diethyl malonate CH2COH O Required alkyl halide CH3CH2CHCH2X CH3 CH3CH2CHCH2 O CH2COH CH3 1-Bromoheptane CH3(CH2)5CH2Br Diethyl malonate CH2(COOCH2CH3)2 Diethyl 2-heptylmalonate CH3(CH2)5CH2CH(COOCH2CH3)2 Nonanoic acid CH3(CH2)5CH2CH2CO2H NaOCH2CH3 ethanol 1. HO, H2O 2. H 3. heat Derived from diethyl malonate CH2COH O Required alkyl halide CH3(CH2) CH3(CH2)5CH2 5CH2X O CH2COH CH2COH O Allyl bromide H CHCH2Br 2C 5-Hexen-2-one CHCH2CH2CCH3 O H2C Ethyl acetoacetate CH3CCH2COCH2CH3 O O 1. NaOCH2CH3 2. HO, H2O 3. H 4. heat Required alkyl halide H2C CHCH2 X Derived from ethyl acetoacetate CH2CCH3 O H2C CHCH2 O CH2CCH3 ESTER ENOLATES 579 Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website