organic chemistry

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organic chemistry

Manu · Accepted Answer

(a) Cyclohexanone → Cyclohexanol derivative with OH and CH₃ groups Suggested Reaction: Addition of a Grignard Reagent : Use methylmagnesium bromide ( CH 3 MgBr 	ext{CH}_3	ext{MgBr} ) in dry ether. This adds a -CH 3 	ext{-CH}_3  group to the ketone carbon and forms an alkoxide intermediate. Acid Workup : Protonate the alkoxide using H 3 O + 	ext{H}_3	ext{O}^+  to form the secondary alcohol. Overall Reaction: Cyclohexanone + CH 3 MgBr → ether , H 3 O + Cyclohexanol with CH 3  group Explanation: It is possible to convert cyclohexanone into the required cyclohexanol derivative by adding a methyl group and reducing the ketone group to an alcohol. Using a Grignard reagent, this is accomplished effectively. Methylmagnesium bromide   ( CH 3 MgBr 	ext{CH}_3	ext{MgBr} )  attacks the carbonyl carbon of cyclohexanone nucleophilically to start the reaction.   As a result, an alkoxide intermediate is created. Following an acid workup with    H 3 O + 	ext{H}_3	ext{O}^+   the alkoxide is protonated and transformed into the appropriate alcohol.   A secondary alcohol with a methyl substituent at the former carbonyl carbon is the product of the efficient and selective process. In organic synthesis, this technique is frequently employed to create alcohols with novel carbon-carbon bonds. (b) 6-Carbon aldehyde with I 	ext{I}  group → 6-Carbon chain with CN 	ext{CN}  and OH 	ext{OH}  plus Ph 	ext{Ph} Suggested Reaction: Cyanide Nucleophilic Substitution : Apply sodium cyanide (NaCN) to the chemical in an aprotic solvent (such as acetone or DMSO). -CN is utilized in place of the iodide group. Addition of Benzyl Grignard Reagent : To add the -Ph group, use phenylmagnesium bromide (PhMgBr). A secondary alkoxide intermediate is produced as a result. Acid Workup : Protonate the alkoxide using H 3 O + 	ext{H}_3	ext{O}^+  to yield the final alcohol. Overall Reaction: I − (CH 2 ) 4 CHO → NaCN , DMSO -CN compound → PhMgBr , H 3 O + Final product Explanation: To change the iodide and aldehyde functionalities, the second transformation requires a sequence of processes. The iodide group is first nucleophilically replaced with a nitrile group using sodium cyanide (NaCN) in an aprotic solvent like DMSO or acetone. The -CN group provides a handle for further functionalization. The Grignard reagent phenylmagnesium bromide (PhMgBr) is then used to add a phenyl group to the carbon next to the nitrile. The reaction's nucleophilic attack on the nitrile carbon results in the production of an alkoxide intermediate. The necessary secondary alcohol with a phenyl substituent is created when the intermediate is protonated during acid workup. This sequence shows how a variety of complex alcohol derivatives can be made using Grignard reagents and nitrile chemistry. (c) Toluene ( CH 3 	ext{CH}_3 ​ ) → Benzyl alcohol ( -CH 2 OH 	ext{-CH}_2	ext{OH} ) Suggested Reaction: Oxidation to Benzaldehyde : Use a mild oxidizing agent or chromium (VI) reagents such as pyridinium chlorochromate (PCC). As a result, the methyl group is specifically oxidized to a benzaldehyde group (-CHO). Reduction to Benzyl Alcohol : Use a reducing agent like sodium borohydride ( NaBH 4 	ext{NaBH}_4 NaBH 4 ​ ) to reduce the aldehyde to a primary alcohol. Overall Reaction: C 6 H 5 CH 3 → PCC C 6 H 5 CHO → NaBH 4 C 6 H 5 CH 2 OH 	ext{C}_6	ext{H}_5	ext{CH}_3 \xrightarrow{	ext{PCC}} 	ext{C}_6	ext{H}_5	ext{CHO} \xrightarrow{	ext{NaBH}_4} 	ext{C}_6	ext{H}_5	ext{CH}_2	ext{OH} Explanation: Oxidation and reduction are two essential processes in the conversion of toluene to benzyl alcohol. First, a moderate oxidizing agent such as pyridinium chlorochromate (PCC) is used to selectively oxidize the methyl group of toluene to a benzaldehyde (-CHO).  The aldehyde's use is preserved by this mechanism, which stops overoxidation. This is followed by the reduction of the aldehyde to a primary alcohol with a reducing agent such as sodium borohydride   NaBH_4 The NaBH 4 	ext{NaBH}_4  selectively reduces the aldehyde to benzyl alcohol without affecting the aromatic ring. This two-step process effectively transforms toluene into benzyl alcohol while preserving high yields and selectivity. Alcohols are frequently made from aromatic precursors using this technique in organic synthesis. Final Answer: (a) Add CH 3 MgBr  	ext{CH}_3	ext{MgBr} to cyclohexanone, followed by acid workup. (b) Replace -I 	ext{-I}  with -CN 	ext{-CN}  using NaCN 	ext{NaCN} , then add PhMg Br 	ext{PhMgBr} and protonate. (c) Oxidize toluene to benzaldehyde with PCC, then reduce to benzyl alcohol with NaBH 4 	ext{NaBH}_4 ​ .

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