Alkynes: Properties, Reactions, and Nomenclature - Prof. Debbie C. Crans, Study notes of Organic Chemistry

Download Alkynes: Properties, Reactions, and Nomenclature - Prof. Debbie C. Crans and more Study notes Organic Chemistry in PDF only on Docsity! 30 September Alkynes Alkynes are similar to alkenes Nomenclature: ending in –yne, position indicated with number Alkyne Reactions Alkynes undergo addition reactions Alkynes are less reactive than alkenes Cation stability on double bond is less – lower reactivity Tertiary > secondary > secondary vinyl > primary > primary vinyl Why are vinyl cations less stable? Structure of cations Alkyl – on sp2 carbon Vinyl – on sp carbon sp carbon is more electronegative than sp2 – closer to nucleus Hyperconjugation less for vinyl cations than alkyl Addition of HX Regioselecitivity Markovnikov vs. anti With one equivalent (same moles reagent as substrate) of HX, addition of one occurs – with excess two adds Geminal dibromide – 2 bromides on same carbon Tautomerization – shift of group and π electrons