Dolbier HW Solutions 496

Dolbier HW Solutions 496 - OCH 2 CH 3 H CH 2 H 2 C O C O C...

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21.20 ( a ) Both carbonyl groups of diethyl malonate are equivalent, and so enolization can occur in either direction. ( b ) Ethyl acetoacetate can give three constitutionally isomeric enols: ( c ) Bromine reacts with diethyl malonate and ethyl acetoacetate by way of the corresponding enols: Br 2 Ethyl acetoacetate CH 3 CCH 2 COCH 2 CH 3 O O Ethyl a -bromoacetoacetate CH 3 CCHCOCH 2 CH 3 Br O O H OCH 2 CH 3 CH O C O C H 3 C OCH 2 CH 3 H CH CH 3 CH 2 O O C O C CH 2 (COOCH 2 CH 3 ) 2 Diethyl malonate Br 2 Diethyl bromomalonate CH 3 CH 2 OCCHCOCH 2 CH 3 Br O O Least stable enol; double bond not conjugated with carbonyl group
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Unformatted text preview: OCH 2 CH 3 H CH 2 H 2 C O C O C CH 3 CCH 2 COCH 2 CH 3 O O Ethyl acetoacetate Enol stable but lacking ester resonance OCH 2 CH 3 CH O C O C H H 3 C Most stable enol; double bond conjugated with carbonyl group; ester carbonyl stabilized by resonance H OCH 2 CH 3 CH O C O C H 3 C Diethyl malonate OCH 2 CH 3 H CH CH 3 CH 2 O O C O C OCH 2 CH 3 CH 2 CH 3 CH 2 O O C C O C OCH 2 CH 3 CH CH 3 CH 2 O O C O H 590 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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