An alkene X (C6H12) gives 3,3-dimethylbutan-1-ol on treatment with BH3.THF and then H2O2/NaOH. The same alkene X with dilute H2SO4 gives mainly 2,3-dimethylbutan-2-ol. X is

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JEE Advanced levelSingle correct optionDifficulty 3 of 3o2199

An alkene X ( $C X_{6} H X_{12}$ ) gives 3,3-dimethylbutan-1-ol on treatment with $BH X_{3} \cdot THF$ and then $H X_{2} O X_{2} / NaOH$ . The same alkene X with dilute $H X_{2} SO X_{4}$ gives mainly 2,3-dimethylbutan-2-ol. X is

A4-methylpent-1-ene
B2,3-dimethylbut-1-ene
C2,3-dimethylbut-2-ene
D3,3-dimethylbut-1-ene

Answer: D

The hydroboration product

(CH X_{3}) X_{3} C - CH X_{2} CH X_{2} OH

shows that X has the skeleton

(CH X_{3}) X_{3} C - CH = CH X_{2}

with a terminal double bond. Acid hydration then goes through a methyl shift to give the rearranged tertiary alcohol. The other alkenes give different hydroboration products.

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An alkene X (CX6​HX12​) gives 3,3-dimethylbutan-1-ol on treatment with BHX3​⋅THF and then HX2​OX2​/NaOH. The same alkene X with dilute HX2​SOX4​ gives mainly 2,3-dimethylbutan-2-ol. X is

Answer: D

More questions on Carbocation rearrangements in addition

An alkene X ( $C X_{6} H X_{12}$ ) gives 3,3-dimethylbutan-1-ol on treatment with $BH X_{3} \cdot THF$ and then $H X_{2} O X_{2} / NaOH$ . The same alkene X with dilute $H X_{2} SO X_{4}$ gives mainly 2,3-dimethylbutan-2-ol. X is