Alkynes Nanoplasmonic Research Group Organic Chemistry Chapter 3 Part IV

Triple bond: sp hybridization

Triple bond: Molecular Orbital

How to Name Alkynes ? 1.Follow alkene rules, but use –yne as suffix 2.If more than one triple bond is present, Use –diyne, -triyne, tetrayne… 3.If both double and triple bonds are present, Use –enyne as suffix Number from side with nearest multiple bond (either double or triple) If a double and triple bond is equidistant, make the double bond the lower number

Examples of Alkynes

Addition Reactions of Alkynes (I) - Reduction - Lindlar’s catalysts Deactivated (poisoned )catalyst Pd, CaCO 3, quinoline

Addition Reactions of Alkynes (II) - Halogen - In case of unsymmetric triple bonds and unsymmetric reagents, please abide by Markovnikov’s rule

Acidity of Alkynes increasing acidity As the hybridization at carbon becomes more s-like and less p-like, the acidity of the attached hydrogen increases !!!