Chapter 15: Q57. (page 570)
Question: Devise a synthesis of each compound from cyclopentane and any other required organic or inorganic reagents.
a.
b.
c.
d.
e.
Short Answer
Answer
a.
b.
c.
d.
e.
Step by step solution
Specific reagents for reaction
- Reagent NBS/ROOR: selective bromination of allylic C-H
- Reagent KOC (CH3)3 : elimination of proton to form an alkene.
- Reagent mCPBA: formation of an achiral epoxide
Step 2: Synthesis using specific reagents with compounds a and b
(a) Cyclopentane is treated with chlorine in the presence of light or heat to form chloro cyclopentane which then reacts with KOC(CH3)3 that forms cyclopentene. It further reacts with acid and water to produce cyclopentanol.
Synthesis of cyclo-pentanol
(b) Cyclopentane is treated with chlorine in the presence of light or heat to form chloro cyclopentane which then reacts with KOC(CH3)3 forming cyclopentene.
Cyclopentene reacts with mCPBA to give 1,2-epoxycyclopentane.
Synthesis of cyclopentene oxide
Synthesis using specific reagents with compounds c, d, and e
(C) Cyclopentane is treated with chlorine in the presence of light or heat to form chloro cyclopentane which then reacts with KOC(CH3)3 forming cyclopentene.
When cyclopentene is treated with NBS, it forms 3-bromocyclopent-1-ene. The latter, on treatment with bromine, gives 1,2,3-tribromocyclopentane
Synthesis of 1,2,3-tribromocyclopentane
(d) Cyclopentane is treated with chlorine in the presence of light or heat to form chloro cyclopentane which then reacts with KOC(CH3)3 forming cyclopentene.
When cyclopentene is treated with NBS, it forms 3-bromocyclopent-1-ene.
3-Bromocyclopent-1-ene reacts with the hydroxide to form cyclopent-2-enol.
Synthesis of 2-cyclopentenol
(e) Cyclopentane is treated with chlorine in the presence of light or heat to form chloro cyclopentane when then reacts with KOC(CH3)3 forming cyclopentene.
When cyclopentene is treated with bromine, it forms 1,2-dichloro cyclopentane. It further reacts with potassium cyanide to form chlorocyclopentancarbonitrile.
Chlorocyclopentancarbonitrile is treated with potassium hydroxide to form 2-hydroxycyclopentane carbonitrile.
Synthesis of 2-hydroxycyclopentane carbonitrile
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