Preparation of Enolates by Deprotonation

The acidifying effect of the remaining acceptor substituents of Table 13.1 decreases in the order —C(=0)—H —C(=0)—alkyl -C(=0)—O-alkyl, and the amide group —C (=0)-NR2 is even less effective. This ordering essentially reflects substituent effects on the 

The equilibrium constant Keq of the respective deprotonation equilibrium shows whether a base can deprotonate a C,H-acidic compound quantitatively, in part, or not at all  

Equation 13.1 shows that these equilibrium constants in turn depend on the acidity constants of the two weak acids involved, that is, the acidity constant K c H acid of the C,H acid and the acidity constant Kti U base of the conjugate acid (H-base) of the base (base ) employed. Equation 13.2 makes the same statement in terms of the corresponding pvalues. From this equation it follows  

Rules of Thumb Regarding the Position of the Equilibria of C,H-Acidic Compounds 

H acid is deprotonated quantitatively (or nearly so) by an equimolar amount of base if the pvalue of the conjugate acid of the base employed is higher than the pA a value of the C,H acid. 

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