Question

Predict the products for the following reactions:

➤ Free Radical

1. $CH_3 \cdot$ →
2. $CH_3 \cdot + Cl \cdot$ →
3. $Cl \cdot$ →
4. Isopropyl radical + $Br \cdot$ →
5. Isopropyl radical →
6. Isopropyl radical + $CH_3 \cdot$ →
7. Isopropyl radical + $Cl \cdot$ →
8. Allyl radical + $Br \cdot$ →
9. Phenoxy radical →
10. Allyl radical →
11. Cyclohexyl radical →
12. $CH_2=CH-CH(CH_3) \cdot$ →
13. Substituted benzyl radical →
14. Isopropyl radical →

➤ Wurtz Reaction 15. $CH_3Cl \xrightarrow{Na \atop dryEt_2O}$ → 16. $PhCH_2Br \xrightarrow{Na \atop dryEt_2O}$ → 17. Propyl bromide $\xrightarrow{Na \atop Dry \ Et_2O}$ 18. Isopropyl bromide $\xrightarrow{Na \atop Dry \ Et_2O}$ 19. tert-Butyl bromide $\xrightarrow{Na \atop Dry \ Et_2O}$ 20. Chlorobenzene $\xrightarrow{Na \atop Dry \ Et_2O}$ 21. 1-chlorocyclohexene $\xrightarrow{Na \atop Dry \ Et_2O}$ 22. 1-chlorocyclohexane $\xrightarrow{Na \atop Dry \ Et_2O}$ 23. 1,2-dichlorocyclohexane $\xrightarrow{Na \atop Dry \ Et_2O}$ 24. 1,4-dichlorocyclohexane $\xrightarrow{Na \atop Dry \ Et_2O}$ 25. 1,4-dichlorocyclohexane $\xrightarrow{Na \atop Dry \ Et_2O}$ 26. 1,2-dichlorobenzene $\xrightarrow{Na \atop Dry \ Et_2O}$ 27. Benzene $\xrightarrow{Na \atop Dry \ Et_2O}$

Answer 1

1. Ethane ($CH_3-CH_3$)
2. Methyl chloride ($CH_3Cl$)
3. Chlorine ($Cl_2$)
4. Isopropyl bromide ($CH(CH_3)_2Br$)
5. 2,3-dimethylbutane ($CH(CH_3)_2-CH(CH_3)_2$)
6. 2-methylbutane ($CH(CH_3)_2-CH_3$)
7. Isopropyl chloride ($CH(CH_3)_2Cl$)
8. Allyl bromide ($CH_2=CH-CH_2Br$)
9. Dimerization (e.g., Diphenyl peroxide $Ph-O-O-Ph$, or C-C coupled products like 4,4'-diphenoxy)
10. 1,5-hexadiene ($CH_2=CH-CH_2-CH_2-CH=CH_2$)
11. Bicyclohexyl
12. Dimer of $CH_2=CH-CH(CH_3) \cdot$
13. Dimer of the substituted benzyl radical
14. 2,3-dimethylbutane ($CH(CH_3)_2-CH(CH_3)_2$)
15. Ethane ($CH_3-CH_3$)
16. 1,2-diphenylethane ($PhCH_2-CH_2Ph$)
17. n-Hexane ($CH_3CH_2CH_2-CH_2CH_2CH_3$)
18. 2,3-dimethylbutane ($CH(CH_3)_2-CH(CH_3)_2$)
19. 2,2,3,3-tetramethylbutane ($(CH_3)_3C-C(CH_3)_3$)
20. Biphenyl
21. Dimer of 1-cyclohexenyl radical
22. Bicyclohexyl
23. Bicyclo[4.1.0]heptane
24. Dimer of cyclohexyl derivative (intermolecular coupling)
25. Dimer of cyclohexyl derivative (intermolecular coupling)
26. Biphenyl
27. No reaction

Answer 2

The questions cover two main topics: Free Radical reactions and Wurtz Reaction.

Free Radical Reactions: These questions involve the formation, reaction, or dimerization of free radicals. A radical is an atom or molecule with an unpaired electron, indicated by a dot ($\cdot$).

• Radical combination/termination: When two radicals combine, they form a stable molecule. For example, $CH_3 \cdot + Cl \cdot \rightarrow CH_3Cl$.
• Radical dimerization: When a single radical species is present, it often dimerizes to form a stable molecule by forming a new bond between two radical centers. For example, $2 CH_3 \cdot \rightarrow CH_3-CH_3$.
• Resonance stabilization: Some radicals, like the phenoxy radical, are resonance stabilized, meaning the unpaired electron is delocalized. Dimerization can occur through coupling at different positions.

Wurtz Reaction: This reaction involves the coupling of two alkyl halide molecules using sodium metal in a dry ethereal solvent (like dry $Et_2O$) to form a new alkane. The general reaction is: $2R-X + 2Na \xrightarrow{dry \ Et_2O} R-R + 2NaX$

• The reaction works best with primary and secondary alkyl halides.
• Tertiary alkyl halides are prone to elimination reactions.
• Aryl halides typically do not undergo Wurtz reaction; they react in Wurtz-Fittig reactions or can form biphenyls under certain conditions.
• Vicinal dihalides can undergo intramolecular cyclization to form cyclic compounds if a stable ring can be formed.