| Reaction |
Example |
Comments |
| Addition of HX |
 |
M's Rule; no stereochem |
| Addition of X2 |
 |
Anti- addition via- halonium ion |
| Halohydrin formation |
 |
Anti- addition via halonium ion; X on more subst. carbon |
| Acid-cat. addition of water |
 |
M's rule; no stereochemistry; yields poor |
| Oxymercuration |
 |
M's rule; no stereochemistry., no rearrangement |
| Hydroboration |
 |
Anti-M, syn addition |
| Syn-hydroxylation |
 |
Forms cis glycol; reductive workup OK also |
| Ozonolysis |
 |
Reductive workup yields aldehyde |
| Ozonolysis |
 |
Oxidative workup gives acid |
| Hydrogenation |
 |
Syn- addition on catalyst surface |
| Oxirane formation |
 |
Oxirane retains stereochem of alkene |
| Dichlorocarbene addition |
 |
Cyclopropane retains stereochemistry of alkene |
| Carbene addition |
 |
Cyclopropane retains stereochemistry of alkene |