Home > Community > Product of treating 1,3‐dibromocyclobutane with alcoholic KOH at elevated temperatures
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+ Biochemistry
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Adrian Aziz Santoso Rian

Product of treating 1,3‐dibromocyclobutane with alcoholic KOH at elevated temperatures

Dennis Leppin  Follow

When 1,2-dibromocyclobutane is heated with KOH, 2 moles of acetylene are formed, probably via a cyclobutadiene intermediate. 1,3-dibromocyclobutane reacts differently.

Here, the final product is vinylacetylene (but-1-en-3-yne, $\ce{HC#C-CH=CH2})$.

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Basecrete Global??  Follow

The two equivalents $\ce{HBr}$ are eliminated from two different molecules, one from the starting material and one from an intermediate. In the first step, $\ce{HBr}$ is eliminated under cleavage of the cyclobutane ring, which is favored by the release of ring strain. Elimination of $\ce{HBr}$ from 1-bromo-1,3-butadiene finally yields but-1-en-3-yne.

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