Chemistry 9701 · AS & A Level · Organic synthesis

Organic synthesis — practice question

Phenylethanone is a significant chemical that has a wide range of applications.
(a)[2]

Phenylethanone may be prepared from benzene as one of the reactants. State the additional reagents used and describe any essential reaction conditions.

(b)[5]

Phenylethanone is tested with three reagents separately. Fill in the table for each reagent by giving the structural formula of one organic product formed and the mechanism name. If no reaction occurs, write ‘no reaction’.

(c(i))[1]

Phenylethanone reacts with HCN in the presence of a small amount of NaCN. Name the mechanism for this reaction.

(c(ii))[4]

Draw the mechanism for this reaction. Include all relevant charges, dipoles, lone pairs and curly arrows. Your mechanism should show the catalytic role of $ ext{CN}^-$ ions.

(d(i))[1]

Draw the structure of compound D in the box.

(d(ii))[1]

Identify a suitable reagent for step 1.

(d(iii))[1]

Identify a suitable reagent for step 2.

(d(iv))[1]

State the number of peaks in the C-13 NMR spectrum of phenylethene.

(d(v))[2]

Suggest C-13 chemical shift ranges expected for the different types of carbon environment in phenylethanone.

Worked solution & mark scheme

This 18-mark question has a full step-by-step worked solution and mark scheme. One marking point: CH$_3$COCl / ethanoyl chloride

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