Alkynes and Their Reactions
Start with the big picture
Each alkyne carbon is sp-hybridized, giving the triple bond a linear arrangement. Terminal alkynes can be deprotonated by strong bases to form acetylide ions, which react with primary alkyl halides to make new carbon–carbon bonds. Alkynes can also be prepared by double dehydrohalogenation of dihalides. Their reactions provide several distinct outcomes: hydrogenation can stop at a cis- or trans-alkene under different conditions or continue to an alkane; addition reactions and hydration produce characteristic intermediates and products; and oxidative conditions can either add oxygen-containing groups or cleave the triple bond. The lesson also introduces acetylide coupling, metathesis, and alkyne trimerization, connecting reaction choice to product structure.
What you'll learn
- Relate sp hybridization to alkyne geometry and bond characteristics.
- Explain terminal alkyne deprotonation and acetylide alkylation.
- Distinguish major alkyne addition and hydration reaction outcomes.
- Compare alkyne hydrogenation conditions and resulting products.
- Identify oxidative cleavage, coupling, and cycloaddition transformations.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
