JEE Main · 2024 · 06 Apr 2024 · Shift 1 · Hydrocarbons

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The major products from the following reaction sequence are product A and product B.

The total sum of π electrons in product A and product B are ______ (nearest integer)

Answer: 8

Solution

Cyclohexene

+ B r_{2}

gives 1,2-dibromocyclohexane.
Product A: reaction with 1.0 eq of sodium propargyloxide (

HC \equiv C - C H_{2} - O^{-} N a^{+}

) replaces one Br, giving the bromocyclohexyl propargyl ether

- O - C H_{2} - C \equiv CH

. Its

π

bonds are only in the

C \equiv C

4

π

electrons.
Product B: with alc. KOH (3 eq), double dehydrohalogenation gives 1,3-cyclohexadiene (two

C = C

4

π

electrons.
Total sum of

π

electrons

= 4 + 4 = 8.

JEE Main · 2024 · 06 Apr 2024 · Shift 1 · Integer answer

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