Question

6. Which series of reactions would best facilitate the following conversion? 1. KMa04 (ag) 2. HgrOAc)2 (ag) 3. NaBIL4OH b) 1. NaBH4 2. H3PO4' 4. H20H3o+ d) 1. NaBH4 e) I. Raney nickel 2. HBr (g) 3. Mg/etber 2. HyC-MgBr 3. H20/H30 7. What compound is prodaced when (R)-pentan-2-ol is treated with TsCI (aka TosCI) followed by Nal? a) sodium (R)-pent-3-oxide b) sodium (S)-pent-2-oxide c) (R)-2-iodopentane d) (S)-2-iodopentane e) none of the above 8. Which of the following reagents is the best choice for oxidizing a primary alcohol to an aldehyde? a) H2Cr04 b) pyridinium chlorochromate c)NazCr20p, H2S04 d) KMn04 c)LiAIH4 9. Which set of reagents will best convert 2,2-dimethylpropan-1-ol to 4,4-dimethylpentan-2-o1? 叭.HCI 2.Mg 3. CH3CHO 4. H30+ b) 1. HCL, ZnCl2 2. Mg 3. CH20 4. H30+ c) 1. soci2 2.Ms 3. CH3CHO 4. H30+ d) 1. HCL, ZnC12 2.Mg 3. CH3CHO 4.H30+ 014 10. Which of the following reagents can be used to convert lo a) TsCl, pyridine followed by d) H2504, heat followed by H2. Pt hn Cle b o e) both A and D 11. Which of the follow'ing reactions or serics of reactions will lad to the formation of 1. Na b) c) d) 2) NaBH4 1. MCPBA e)

Answer 1

6.

Correct option : b)

NaBH4 will reduce the ketone to alcohol. Then acid catalyzed dehydration using H₃PO₄ under heating will give the product.

Phosphoric acid first protonate the alcoholic -OH group to good leaving group -OH₂⁺. Then water elimination and subsequent carbocation rearrangement will give the product.

1. NaBH4 2 . H3PO4/A : ОН он OH2 он он он

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7.

Correct option: d)

OH OTs TsCl Nal (S)-2-iodopentane (R)-pentan-2-ol

Conversion of -OH to good leaving group -OTs followed by S_N2 reaction with I^- gives the product with inversion of configuration at the stereocenter.

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8.

Correct option: b)

Pyridinium chlorochromate oxidizes primary alcohol to aldehyde. The oxidation stops at aldehyde stage with this reagent.

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9.

Correct option: c)

1. SOCI2 2. Mg 3. CH3CHO 4. H30+ но BrMgO но 2,2-dimethylpropan-1-ol 4.4-dimethylpentan-2-ol