O-Chem Reactions of Alkenes

Halohydrin Reaction (Br & H2O)

A reaction introducing Br and H2O where Br and OH break the double bond (anti-addition). OH goes to more substituted carbon, Br goes to less substituted carbon. 

Hydration Reaction (H2O & H+)

A reaction that involves the addition of H2O and H+, H goes to less substituted and OH goes to more substituted (Markovnikov)

Hydroboration-Oxidation (1. BH3/THF 2. H2O2/OH-)

OH goes to less substituted, H goes to more substituted, Anti-Markovnikov

Dihydroxilation (Cold KMnO4)

Adds OH & OH, both OH on same face (both facing forwards or both facing backwards)

Ozonolysis (O3)

Cleaves the double bond completely, creating two carbonyl groups

Catalytic Hydrogenation (H2 & Ni/Pd/Pt)

Adds H & H across the double bond (syn-addition)

Epoxidation (mcpBA)

Replace double bond with triangle containing oxygen. However, in presence of mcpBA and H2O/H+ two OH’s are added in anti addition format on the carbons from the double bond.

Halogenation (Br2/Cl2)

Adds the two halogens across the double bonds (anti-addition, one forward and one back) on adjacent carbons

Hydrogenation (H-Br/ Markov)

H goes to the less substituted, Br goes to more substituted

Hydrogenation (H-Br and ROOR/ Anti-Markov) 

H goes to more substituted, Br goes to less substituted. 

What’s the difference between more substituted and less substituted?

More substituted means bonded to more Carbons, Less substituted means bonded to less carbons (and therefore more Hydrogens)