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Question: Choose the correct alkyne which gives alkanal on hydroboration and hydrolysis. (A)- \(C{{H}_{3}}-C...

Choose the correct alkyne which gives alkanal on hydroboration and hydrolysis.
(A)- CH3−C≡C−CH3C{{H}_{3}}-C\equiv C-C{{H}_{3}}
(B)- CH3−CH2−CH=CH−C≡CHC{{H}_{3}}-C{{H}_{2}}-CH=CH-C\equiv CH
(C)- CH3−C≡CHC{{H}_{3}}-C\equiv CH
(D)- CH3−CH2−C≡C−CH3C{{H}_{3}}-C{{H}_{2}}-C\equiv C-C{{H}_{3}}

Explanation

Solution

Alkanes also known as aldehyde are a class of organic compounds in which a carbon atom shares a double bond with an oxygen atom, a single bond with a hydrogen atom and a single bond with another group of atom or atoms.

Complete answer:
-Let us first understand hydroboration and hydrolysis.
-Hydroboration is the process in which the hydrogen boron bond is added to a double bond between either carbon and carbon or carbon-nitrogen atoms. Hydroboration can also be performed on a carbon-carbon triple bond.
-Hydrolysis is a chemical process in which a molecule of water is added to a substance.
-Let us now consider each option one by one.
-In option A, CH3−C≡C−CH3C{{H}_{3}}-C\equiv C-C{{H}_{3}} is given which is an internal alkyne. This alkyne on hydroboration and hydrolysis gives CH3−CH2−CO−CH3C{{H}_{3}}-C{{H}_{2}}-CO-C{{H}_{3}}.
-In option B, CH3−CH2−CH=CH−C≡CHC{{H}_{3}}-C{{H}_{2}}-CH=CH-C\equiv CH is given which is a terminal alkyne. This alkyne on hydroboration and hydrolysis gives CH3−CH2−CH=CH−CH2CHOC{{H}_{3}}-C{{H}_{2}}-CH=CH-C{{H}_{2}}CHO.
-In option C, CH3−C≡CHC{{H}_{3}}-C\equiv CHis given which is a terminal alkyne. This alkyne on hydroboration and hydrolysis gives CH3−CH2−CHOC{{H}_{3}}-C{{H}_{2}}-CHOwhich is an alkanal.
-In option D, CH3−CH2−C≡C−CH3C{{H}_{3}}-C{{H}_{2}}-C\equiv C-C{{H}_{3}}is given which is an internal alkyne. This alkyne on hydroboration and hydrolysis gives CH3−CH2−CH=CH−CH2CHOC{{H}_{3}}-C{{H}_{2}}-CH=CH-C{{H}_{2}}CHO .

Hence, the correct answer is option C.
CH3−C≡CH→hydrolysishydroborationCH3−CH=CHOH→keto-enol tautomerismCH3−CH2−CHOC{{H}_{3}}-C\equiv CH\xrightarrow[hydrolysis]{hydroboration}C{{H}_{3}}-CH=CHOH\xrightarrow{\text{keto-enol tautomerism}}C{{H}_{3}}-C{{H}_{2}}-CHO

Note:
-Alkanes are organic molecules which contain only carbon (C), hydrogen (H), and oxygen (O) atoms.
-Alkanes belong to the group of organic compounds known as aldehydes.
-Aldehydes contain a carbonyl function group.
-A straight-chain alkanal consists of a chain of 1 or more carbon atoms joined to each other by single covalent bonds, with a carbonyl functional group attached to the terminal carbon atom in the chain of carbons.