2-Bromo-3,3-dimethylbutane, CH3-CHBr-C(CH3)3, is heated in ethanol with no added base. The major substitution product is

JEE Main levelSingle correct optionDifficulty 2 of 3o3013

2-Bromo-3,3-dimethylbutane, $CH X_{3} - CHBr - C (CH X_{3}) X_{3}$ , is heated in ethanol with no added base. The major substitution product is

Ionisation gives the secondary cation

CH X_{3} - CH X^{+} - C (CH X_{3}) X_{3}

. A 1,2-methyl shift from the quaternary carbon gives the tertiary cation

(CH X_{3}) X_{2} C X^{+} - CH (CH X_{3}) X_{2}

. Ethanol captures this cation to give

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

, i.e. 2-ethoxy-2,3-dimethylbutane.