Predict the direction of the following equilibrium and the approximate value of Keq.
$R_{3} COH$ + (enolate of an ester $R_{2} CH - CO - O R^{'}$ ) $⇌$ $R_{3} C O^{-}$ + $R_{2} C H_{2} - CO - O R^{'}$ ( $p K_{a}$ ≈ 18 and ≈ 25)

Question

Predict the direction of the following equilibrium and the approximate value of Keq.

$R_{3} COH$ + (enolate of an ester $R_{2} CH - CO - O R^{'}$ ) $⇌$ $R_{3} C O^{-}$ + $R_{2} C H_{2} - CO - O R^{'}$ ( $p K_{a}$ ≈ 18 and ≈ 25)

TestHub · Accepted Answer

The acid on the left is the tertiary alcohol ( p K a ​ ≈ 18) and the acid on the right is the ester α C-H ( p K a ​ ≈ 25). The weaker acid is on the right, so the equilibrium favours the products : a tertiary alkoxide is easily basic enough to form an ester enolate. Keq ≈ 1 0 25 − 18 = 1 0 7 ⋅

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