Chemistry 9701 · AS & A Level · Organic synthesis

Organic synthesis — practice question

Menthone, $\text{C}_{10}\text{H}_{18}\text{O}$, is a cyclic ketone found in oil of peppermint.
(a)[2]

On the formula above, use asterisks (*) to show any chiral centres in the menthone molecule.

(b(i))[2]

Suggest reagents for step 1, step 2.

(b(ii))[2]

Suggest structures for $L$ and $M$ and draw them in the boxes above.

(c(i))[1]

Give the letter of the alkene that formed $N$ in this reaction.

(c(ii))[1]

Suggest the structure of product $P$ from the reaction between the other alkene you have drawn and hot concentrated acidified $\text{KMnO}_4$.

(c(iii))[1]

Suggest one chemical test that would allow you to tell $N$ and $P$ apart. reagent(s) what is seen

(d)[3]

Suggest the mechanism of this 2-stage reaction by means of a diagram. Show all whole or partial charges, and use curly arrows to represent the movement of electron pairs.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: Each correctly identified chiral centre

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