JEE Main · 2022 · 28 Jul 2022 · Shift 1 · Haloalkanes and Haloarenes

Identify the correct statement for the below given transformation.

(A)A $- CH_{3} CH_{2} CH = CH - CH_{3}$ , $B - CH_{3} CH_{2} CH_{2} CH = CH_{2}$ , Saytzeff products
(B) $A - CH_{3} CH_{2} CH = CH - CH_{3}$ , $B - CH_{3} CH_{2} CH_{2} CH = CH_{2}$ , Hafmann products
(C)A $- CH_{3} CH_{2} CH_{2} CH = CH_{2}$ , $B - CH_{3} CH_{2} CH = CHCH_{3}$ , Hofmann products✓ Correct
(D)A $- CH_{3} CH_{2} CH_{2} CH = CH_{2}$ , $B - CH_{3} CH_{2} CH = CHCH_{3}$ , Saytzeff products

Answer: (C)

Solution

In elimination reactions from quaternary ammonium salts (Hofmann elimination), the less substituted alkene (Hofmann product) is favored due to steric hindrance. Product A is

CH_{3} CH_{2} CH_{2} CH = CH_{2}

(terminal alkene, less substituted) and product B is

CH_{3} CH_{2} CH = CHCH_{3}

(internal alkene, more substituted). Both are Hofmann products, with A being the major product.

JEE Main · 2022 · 28 Jul 2022 · Shift 1 · Single correct option

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JEE Main · 2022 · 28 Jul 2022 · Shift 1 · Haloalkanes and Haloarenes

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