CAIE A Level Chemistry 9701 · Organic synthesis

Organic synthesis: suggest question

Suggest7 marksChallenge

A student plans to prepare 2-hydroxy-3-methylbutanoic acid, $\ce{CH3CH(CH3)CH(OH)COOH}$ , starting from 2-methylpropanal, $\ce{(CH3)2CHCHO}$ .

(a) The first step is to convert the aldehyde into a cyanohydrin using $\ce{HCN}$ .

Suggest a reagent and conditions for this step, and name the functional group formed.

(b) The cyanohydrin is then hydrolysed to the hydroxy acid.

Suggest the reagent and conditions for this step, and name the type of reaction.

Name the functional group formed and the type of reaction.

(d) State one possible by-product of the reaction in (c), and explain why it forms.

How this question is marked

7 marks, so the mark scheme is looking for about 7 separate creditworthy points. Making the same point twice in different words earns it once.

Suggest means: Apply what you know to an unfamiliar situation. There may be more than one acceptable answer. Reason from the principle you have learned to the new context, and say which principle you are using.

Organic synthesis: suggest question

How this question is marked

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