Organic Chemistry I

Chem 334 - Fall 2009

Chapter 6 Notes

Professor Carl C. Wamser

Alkene Reactions

Reaction Types

Alkene Addition Reactions

Addition Mechanism

Addition of HX to Alkenes

Orientation of Addition - Regiochemistry

Markovnikov's Rule

Markovnikov Addition

Hydration of Alkenes

Hydration Mechanism

Anti-Markovnikov Addition of HBr

follows a different mechanism involving free radicals

Br• adds first, forming the more stable (more substituted) radical

H is added second (from HBr) - to the more substituted C (anti-Markovnikov)

Catalytic Hydrogenation

CH2=CH2 + H2 ---> CH3-CH3

Stereochemistry - Syn Addition

1,2-dimethylcyclohexene + H2 --(cat)-->cis-1,2-dimethylcyclohexane (no trans)

Halogenation of Alkenes

CH2=CH2 + Cl2 ---> Cl-CH2-CH2-Cl

Stereochemistry - Anti Addition

cyclopentene + Br2 ---> trans-1,2-dibromocyclopentane (no cis)

Bromonium Ion


Halohydrins

Hydroboration/Oxidation

Oxidation of Alkenes

Epoxidation

addition of O to C=C, forms epoxide ring

reagent is peroxyacid ( RCO3H )

Oxidative Cleavage

C=C --> C=O + O=C