Dolbier HW Solutions 489

Dolbier HW Solutions 489 - 583 ESTER ENOLATES Basic ester...

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Unformatted text preview: 583 ESTER ENOLATES Basic ester hydrolysis followed by acidification and decarboxylation gives the diketone 3-(2oxopropyl)cycloheptanone as the major product of the reaction sequence. O O O O 1. KOH, ethanol–water CHCOCH2CH3 2. H 3. heat CH2CCH3 C O 21.14 (b) 3-(2-Oxopropyl)cycloheptanone (52%) CH3 The -carbon atom of the ester bears a phenyl substituent and a methyl group. Only the methyl group can be attached to the carbon by nucleophilic substitution. Therefore generate the enolate of methyl phenylacetate with lithium diisopropylamide (LDA) in tetrahydrofuran (THF) and then alkylate with methyl iodide. OLi LDA THF C6H5CH2CO2CH3 C6H5CH CH3I C C6H5CHCO2CH3 OCH3 Methyl phenylacetate (c) CH3 Enolate of methyl phenylacetate Methyl 2-phenylpropanoate The desired product corresponds to an aldol addition product. OH O O O CHC6H5 HCC6H5 Therefore convert cyclohexanone to its enolate and then treat with benzaldehyde. O OH O CHC6H5 1. LDA, THF 2. C6H5CHO 3. H3O Cyclohexanone (d ) 1-(2-Oxocyclohexyl)-1phenylmethanol This product corresponds to the addition of the enolate of tert-butyl acetate to cyclohexanone. OH CH2COC(CH3)3 O CH2COC(CH3)3 O O Generate the enolate of tert-butyl acetate with lithium diisopropylamide; then add cyclohexanone. CH3CO2C(CH3)3 1. LDA, THF 2. cyclohexanone 3. H3O tert-Butyl acetate Back Forward Main Menu TOC Study Guide TOC OH CH2CO2C(CH3)3 tert-Butyl (1-hydroxycyclohexyl)acetate Student OLC MHHE Website ...
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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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