Chemistry - What will be the product when 3,4-dibromocyclohexene is reacted with sodium followed by heating with selenium?

Assuming your Product A is correct then product B should be benzene. Selenium act as a mild oxidizing agent at temperature 220 °C to 330 °C. In the above reaction selenium oxidizes cyclohexadiene to form benzene.

Below is a reaction in which 1-methyl-1,3-cyclohexadiene is converted into toluene.

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