Caiboxylic esters synthesis

The thennal decarboxylation of malonic acid derivatives is the last step in a multistep synthesis of caiboxylic acids known as the malonic ester synthesis. This synthetic method will be described in Section 21.7. 

Usually the Knoevenagel condensation yields the unsaturated product, but, with appropriate aldehydes, P-hydroxymalonates can be isolated. The unusual formation of an a-naphthol (74) has been reported from the reaction of diphenylacetaldehyde (73) with diethyl malonate under Knoevenagel conditions." Condensation of stdicyl dehydes and other aromatic o-hydroxy aldehydes with malonates is still in use for the synthesis of the corresponding coumarin-3-caiboxylic esters (75). Reduction... 

Stereoselective addition of a dithiane ankm to dural 2-mediyl-3-trimethylsilyl-3-butenal combined with the stereoselective addition of a Grignard leagmt to the chiral a-alkoxy ketone affords a practical method for the construction of a,7-dimethyl-a,p-dihydroxy compounds, useful intemiediates fra the synthesis of erythronolides (Scheme 33). P-Hydroxy carboxylic esters were synthesized by the addition of ethyl 1,3-dithiolanyl-2-caiboxylate enolate to a chiral ald yde, followed by desidfiirization. ... 

Al-Dweik M, Zahra J, Khanfar M, El-Abadelah M, Zeller K, Voelter W (2009) Hderocycles [h]-fiisedto 4-oxoquinoline-3-catboxylic add. Part Vll synthesis of some 6-oxoimidazo[4,5-h]quinoline-7-caiboxylic adds and esters. Monatsh Chem 140 221—228... 

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