Unit IV: Addition reactions of Alkenes

alkenes have p-orbitals defining the

second bond, with electron density above and below the trigonal planar molecule

addition reactions occur from

top or bottom faces

hydrogenation

the addition of H2

what does hydrogenation allow

Preparation of saturated hydrocarbons from alkenes 

metal catalysts faciliate the

reaction in heterogeneous conditions with solid catalyst

more stable alkenes have lower heats of

hydrogenation because they start with less PE

Pi electrons create regions of

high electron density above and below the trigonal planar carbons making alkenes nucleophilic

electrophiles have regions of 

positive charge that react with nucleophilic double bonds

Markovnikov’s rule

hydrogen adds to the carbon with more hydrogens

Markovs rule reflects

carbocation stability which generates the most susbituted carbocation

Achiral reagents give

a chiral products

Hydration of alknes can occur via 

formation of h30 with a strong acid 

each step is fully

reversible

hydration and dehydration are

two sides of an equilibrium

le chateliers principle

removing volatile alkenes drives elimination