(R)-Octan-2-ol is treated successively with (i) TsCl in pyridine, (ii) NaN3 in DMF (clean SN2), and (iii) H2 over Pd/C, which reduces the azide to the amine without touching the C-N bond. The final octan-2-amine is

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(R)-Octan-2-ol is treated successively with (i) TsCl in pyridine, (ii) $NaN X_{3}$ in DMF (clean SN2), and (iii) $H X_{2}$ over Pd/C, which reduces the azide to the amine without touching the C-N bond. The final octan-2-amine is

A(S)-octan-2-amine
B(R)-octan-2-amine
Cracemic octan-2-amine
Doctan-2-one

Answer: A

Step (i) forms the tosylate at oxygen and does not touch the stereocentre. Step (ii) is a single SN2 displacement with inversion. Step (iii) retains the carbon configuration. The priority order (

O / N > C X_{3} > CH X_{3} > H

) is the same at every stage, so a single inversion changes R into S: (S)-octan-2-amine.

Practice Organic Reaction Mechanisms III: Nucleophilic Substitution More on SN1 vs SN2: substrate, nucleophile, solvent, leaving group

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(R)-Octan-2-ol is treated successively with (i) TsCl in pyridine, (ii) NaNX3​ in DMF (clean SN2), and (iii) HX2​ over Pd/C, which reduces the azide to the amine without touching the C-N bond. The final octan-2-amine is

Answer: A

More questions on SN1 vs SN2: substrate, nucleophile, solvent, leaving group

(R)-Octan-2-ol is treated successively with (i) TsCl in pyridine, (ii) $NaN X_{3}$ in DMF (clean SN2), and (iii) $H X_{2}$ over Pd/C, which reduces the azide to the amine without touching the C-N bond. The final octan-2-amine is