Dolbier HW Solutions 500

Dolbier HW Solutions 500 - – 180 8 C COH O C 10 H 18 O 2...

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( c ) Both ester function undergo hydrolysis in acid, but decarboxylation occurs only at the carboxyl group that is b to the ketone carbonyl. ( d ) A Dieckmann cyclization occurs, giving a f ve-membered ring fused to the original three- membered ring. ( e ) Saponi f cation and decarboxylation convert the b -keto ester to a ketone. 21.24 The heart of the preparation of capsaicin is a malonic ester synthesis. The f rst step is bromination of the primary alcohol by phosphorous tribromide. The resulting primary alkyl bromide is used to alkylate the sodium salt of diethyl malonate. A substituted malonic acid derivative is obtained following basic hydrolysis of the ester groups. Malonic acid derivatives undergo decarboxylation on heating. heat 160
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Unformatted text preview: – 180 8 C COH O C 10 H 18 O 2 COH O O COH OH PBr 3 1. NaCH(CO 2 CH 2 CH 3 ) 2 2. KOH, H 2 O, heat 3. H 1 Br C 8 H 15 Br COH O O COH C 11 H 18 O 4 1. HO 2 , H 2 O 2. H 1 3. heat O H H Bicyclo[3.1.0]hexan-3-one (C 6 H 8 O, 43%) COOCH 2 CH 3 O H H Ethyl bicyclo[3.1.0]hexan-3-one-2-carboxylate 1. NaOCH 2 CH 3 2. H 1 CH 2 COOCH 2 CH 3 CH 2 COOCH 2 CH 3 H H Diethyl cis-1,2-cyclopropanediacetate COOCH 2 CH 3 H H O Ethyl bicyclo[3.1.0]-hexan-3-one-2-carboxylate (C 9 H 12 O 3 , 79%) Diethyl 2-methylcyclopentanone-3,5-dicarboxylate O COOCH 2 CH 3 COOCH 2 CH 3 H 3 C O CO 2 H CO 2 H H 3 C 2-Methylcyclopentanone-3-carboxylic acid (C 7 H 10 O 3 ) O CO 2 H H 3 C H 3 O 1 heat 594 ESTER ENOLATES...
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This note was uploaded on 09/30/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.

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