Aldehydes and Ketones - Result Question 16
####16. The number of aldol reaction(s) that occurs in the given transformation is
(2012)
(a) 1
(b) 2
(c) 3
(d) 4
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Answer:
Correct Answer: 16. (b)
Solution:
- The given reaction is an example of repeated aldol condensation followed by Cannizzaro reaction.
Step I $CH _3 CHO+OH^{-} \longrightarrow \overline{C} H _2-CHO+H _2 O$
Step II $HOCH _2-CH _2-CHO+HO^{-} \rightleftharpoons$
$$ HO-CH _2-\overline{C} H-CHO+H _2 O $$
$H-\stackrel{O}{O}-H+\underset{CH _2 OH}{\stackrel{-}{C} H}-CHO \rightleftharpoons$
Step III $HOCH _2-\underset{CH _2 OH}{CH}-CHO+HO^{-} \rightleftharpoons$
$HOCH _2-\underset{CH _2 OH}{\overline{C}-CHO+H _2 O}$
In the last step, formaldehyde is oxidised and the other aldehyde is reduced giving the desired products.
