lecture 19.3

Lecture 19.3 - 19-19-1Organic Organic H BrownWilliam H BrownChristopher S FooteChristopher S FooteBrent L IversonBrent L Iverson19-19-2Enolate

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Unformatted text preview: 19-19-1Organic Organic ChemistryChemistryWilliam H. BrownWilliam H. BrownChristopher S. FooteChristopher S. FooteBrent L. IversonBrent L. Iverson19-19-2Enolate AnionsEnolate AnionsChapter 19Chapter 1919-19-3Malonic Ester SynthesisMalonic Ester Synthesis◆The strategy of a malonic ester (ME) synthesis is identical to that of an acetoacetic ester synthesis, except that the starting material is a β-diester rather than a β-ketoesterOEtOCCH2COEtOORRCHCOHRCH2COHOA disubstitutedacetic acidA monosubstitutedacetic acidDiethyl malonate(Malonic ester)19-19-4Malonic Ester SynthesisMalonic Ester Synthesis◆Consider the synthesis of this target moleculeMeOOHO5-Methoxypentanoic acidThese two carbonsare from diethyl malonate19-19-5Malonic Ester SynthesisMalonic Ester Synthesis•treat malonic ester with an alkali metal alkoxide•alkylate with benzyl chlorideCOOEtCOOEtEtO- Na++Na+COOEtCOOEtEtOHEthanolpKa 15.9(weaker acid)Sodium ethoxideSodium salt of diethyl malonate+Diethyl malonatepKa 13.3(stronger acid)MeOBrNa+COOEtCOOEtCOOEtCOOEtMeONa+ Br-++SN219-19-6Malonic Ester SynthesisMalonic Ester Synthesis•saponify and acidify•decarboxylation2EtOH+COOEtCOOEtMeO3. NaOH, H2O4. HCl, H2OCOOHCOOHMeOCOOHCOOHMeOheatMeOCOOHCO2+5-Methoxypentanoic acid19-19-7Michael ReactionMichael Reaction...
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This note was uploaded on 03/30/2008 for the course CHEM 262 taught by Professor Forbes during the Spring '08 term at UNC.

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Lecture 19.3 - 19-19-1Organic Organic H BrownWilliam H BrownChristopher S FooteChristopher S FooteBrent L IversonBrent L Iverson19-19-2Enolate

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