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Alcohols, Phenols and Ethers
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Given below are two statements: Statement I: Propene on treatment with diborane gives an addition product with the formula $((CH_3)_2CH)_3B$. Statement II: Oxidation of $((CH_3)_2CH)_3B$ with hydrogen peroxide in presence of NaOH gives propan-2-ol. In the light of the above statements, choose the most appropriate answer from the options given below:Hydroboration of propene is anti-Markovnikov, so boron attaches to the less hindered terminal carbon, giving $(CH_3CH_2CH_2)_3B$ (not $((CH_3)_2CH)_3B$) — so Statement I is incorrect. However, oxidation of a borane such as $((CH_3)_2CH)_3B$ with $H_2O_2/NaOH$ does proceed with retention of configuration to replace the C–B bond with a C–OH bond, giving propan-2-ol, so Statement II (as a statement of the oxidation step) is correct.
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Identify D in the following sequence of reactions: $CH_3CH_2OH\xrightarrow{P+I_2}A\xrightarrow[dry\ ether]{Mg}B\xrightarrow{HCHO}C\xrightarrow{H_2O}D\ (major)$$CH_3CH_2OH\xrightarrow{P+I_2}CH_3CH_2I$ (A); $CH_3CH_2I\xrightarrow{Mg,\ dry\ ether}CH_3CH_2MgI$ (B, Grignard reagent); $CH_3CH_2MgI$ reacts with HCHO to give an addition product, which on hydrolysis with $H_2O$ gives $CH_3CH_2CH_2OH$ (D, n-propyl alcohol, major product).