CHAPTER 21 ESTER ENOLATES SOLUTIONS TO TEXT PROBLEMS 21.1 Ethyl benzoate cannot undergo the Claisen condensation, because it has no protons on its a-carbon atom and so cannot form an enolate. Ethyl pentanoate and ethyl phenylacetate can undergo the Claisen condensation 1. NaOCH( 2CH,CH, CH,CH,COCH, CH 2.H2O CHa CH, CH,CH,CCHCOCH2 CH3 CH,CH, CH Ethyl pentanoate Ethyl 3-ox0-2-propylheptanoate 2C.H CH, COCH, CH2 CHCHCCHCOCH,CH 21.2 (b) The enolate formed by proton abstraction from the a-carbon atom of diethyl 4-methylhep- anedioate cyclizes to form a six-membered B-keto ester LOCHICH3 OCHCH CH CHCH OCCH CH CHCH. CH COCH, CH, NaccHlCH3, Ch,Ch o H,C CHCH3 Diethyl 4-methy lheptanedioate Ethyl (5-methyl-2-oxocyclohexane)- carboxylate 576 Back Forward Main Menu TOC Study Guide Toc Student OLC MHHE WebsiteCHAPTER 21 ESTER ENOLATES SOLUTIONS TO TEXT PROBLEMS 21.1 Ethyl benzoate cannot undergo the Claisen condensation, because it has no protons on its -carbon atom and so cannot form an enolate. Ethyl pentanoate and ethyl phenylacetate can undergo the Claisen condensation. 21.2 (b) The enolate formed by proton abstraction from the -carbon atom of diethyl 4-methylhep￾tanedioate cyclizes to form a six-membered -keto ester. CH3CH2OCCH2CH2CHCH2CH2COCH2CH3 CH3 O O CH3CH2O NaOCH2CH3 OCH2CH3 CH3 O O C Ethyl (5-methyl-2-oxocyclohexane)- carboxylate Diethyl 4-methylheptanedioate OCH2CH3 O O C C H2C CHCH3 CH2 CH2 CH 2C6H5CH2COCH2CH3 O Ethyl phenylacetate Ethyl 3-oxo-2,4-diphenylbutanoate C6H5CH2CCHCOCH2CH3 O O C6H5 1. NaOCH2CH3 2. H3O 2CH3CH2CH2CH2COCH2CH3 O Ethyl pentanoate Ethyl 3-oxo-2-propylheptanoate CH3CH2CH2CH2CCHCOCH2CH3 O O CH2CH2CH3 1. NaOCH2CH3 2. H3O 576 Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website