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Alkyne Nomenclature
• Replace “-ane” with “-yne”– Terminal alkynes 1-
butyne
– Internal alkynes 2-pentyne
Alkyne Nomenclature
• Replace “-ane” with “-yne”– Terminal alkynes 1-butyne
– Internal alkynes 2-pentyne
• Alkyne is given lowest number
Alkyne Nomenclature
• When more than one triple bond use diene, triene.......
• If a double and a triple bond are present, number to give the lowest #
• If multiple functional groups are present, use both suffixes.
Physical Properties
• All hydrocarbons have similar properties• Alkynes similar to alkenes and alkanes
– Less dense than water– Low polarity– Bp increase with MW
• Alkynes are more linear than alkenes• Triple bond is more polarizable than C=C• Stronger van der Waals interactions
Reaction Considerations
• Alkynes are e- rich (they are nucleopliles)• Alkynes undergo electrophilic addition Rx• Regioselective addition (Markovnikov’s Rule)• The resulting alkene can also react
Alkyne Reactions
• Hydrogen Halide addition• Addition of Water• Mercuric-ion-catalyzed hydration• Hydroboration – oxydation• Hydrogenation
– Pd or Pt– Lindlars– Na or Li
• Acetylice ion