Carbon nucleophiles intra-intermolecular reactions

In the Claisen condensation mechanism, the sodium methoxide removes an acidic hydrogen from the carbon a to the carbonyl carbon, resulting in the formation of an enolate ester (Wiedermann et al., 1961). This reaction produces a carbanion, a powerful nucleophile. This nucleophile will attack carbonyl groups, forming a P-keto ester intermediate and a glycerylate. The glycerylate is now free to attack other carbonyl carbons and exchange esters intra- and intermolecularly. Once this carbanion is created, the same considerations as for the usual carbonyl carbon chemistry apply. 

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