The enantiopure secondary benzylic chloride shown is studied under two conditions: (i) NaN3 at high concentration in DMF, and (ii) hydrolysis in aqueous acetone with no added nucleophile. Select all correct statements.

Condition (i) gives mainly the azide with inverted spatial arrangement

Condition (ii) gives an alcohol with much reduced optical purity (largely racemised)

Condition (i) gives mainly the azide with inverted spatial arrangement

Condition (ii) gives an alcohol with much reduced optical purity (largely racemised)

Adding NaOH to condition (ii) increases the S_N1 rate in proportion to [OH-]

A p-methoxy group on the ring would slow condition (ii)

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The enantiopure secondary benzylic chloride shown is studied under two conditions: (i) $NaN X_{3}$ at high concentration in DMF, and (ii) hydrolysis in aqueous acetone with no added nucleophile. Select all correct statements.

ACondition (i) gives mainly the azide with inverted spatial arrangement
BCondition (ii) gives an alcohol with much reduced optical purity (largely racemised)
CAdding $NaOH$ to condition (ii) increases the $S X_{N} 1$ rate in proportion to $[OH X^{-}]$
DA p-methoxy group on the ring would slow condition (ii)

Answer: A, B

The compound is (S)-(1-chloroethyl)benzene. (i) Concentrated azide in DMF forces bimolecular substitution, giving the azide with inverted spatial arrangement. (ii) Solvolysis goes through the planar benzylic cation, so the alcohol is largely racemised (a small excess of inversion may remain, but most optical activity is lost). The

S X_{N} 1

rate does not depend on hydroxide concentration, so adding

NaOH

does not speed it, and a p-methoxy group stabilises the cation and speeds the reaction rather than slows it. Correct: the first two.

Practice Organic Reaction Mechanisms III: Nucleophilic Substitution More on SN1 vs SN2 preference and rate order for drawn substrates

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The enantiopure secondary benzylic chloride shown is studied under two conditions: (i) NaNX3​ at high concentration in DMF, and (ii) hydrolysis in aqueous acetone with no added nucleophile. Select all correct statements.

Answer: A, B

More questions on SN1 vs SN2 preference and rate order for drawn substrates

The enantiopure secondary benzylic chloride shown is studied under two conditions: (i) $NaN X_{3}$ at high concentration in DMF, and (ii) hydrolysis in aqueous acetone with no added nucleophile. Select all correct statements.