The major product of the following reaction is: C_6H_5CH_2 - C(CH_3)(Br) - CH_2 - CH_3 with C_2H_5ONa/C_2H_5OH .

JEE Main 2017 Chemistry question

The major product of the following reaction is: \mathrm{C_6H_5CH_2{-}C(CH_3)(Br){-}CH_2{-}CH_3} with .

(1)\mathrm{C_6H_5CH{=}C(CH_3)CH_2CH_3}Correct
(2)
(3)\mathrm{C_6H_5CH_2{-}C(CH_3)(OC_2H_5){-}CH_2CH_3}
(4)\mathrm{C_6H_5CH_2{-}C(CH_2CH_3){=}CHCH_3}

Answer: (1)

Solution

Sodium ethoxide in ethanol is a strong base acting on a **tertiary** benzylic-adjacent bromide, so elimination (E2) dominates completely over substitution — a tertiary centre is far too hindered for , which rules out the ether in option (3). The question is then which -hydrogen is removed. Two

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Question ID VK-115818