[Astrokel]

hey sir/madam,

i have a question as attached. It is a MCQ question and no explanation is given only answer C, so would you mind telling me if my reasoning is right.

A is wrong because after performing (1) and (2), a carboxylic salt is obtained which makes (3) not possible

B is wrong because the cyanide group will undergo base and acidic hydrolysis thus interfering the obtaining of compound A, thus achieving low yield?

C will achieve a high yield due to the rapid acylation in (1)

D will be achieve lower yield than C, but why? Acylation is the faster?

[sjb]

In the first instance, cyanohydrin formation is reversible, so it would be better to do that as late as possible in a synthesis to avoid decomposition back to the aldehyde. It's also dangerous in so much as you'd be releasing HCN (a poison).

I'm not sure if that's the sort of reasoning you want, but it may be suitable at A-Level.

S

[Astrokel]

I see your point, which makes B and D lower yield since they form cyanohydrin earlier. Are there any wrong with my reasonings?

thanks alot sir.