Substitution reactions occur when two reactants exchange parts to give two new products. In a substitution, one replaces another

21.11 Aryl Halide and Nucleophilic Aromatic Substitution 21.12 Spectroscopic Analysis of Phenols and Aryl Halides

17.7 Lithium Enolates 17.8 α-Selenation: A Synthesis of α,β-Unsaturated Carbonyl Compounds 17.9 Additions to α,β-Unsaturated Aldehydes and Ketones

The aldols formed in aldol additions can be easily dehydrated to yield conjugated enals (enones)

If a chiral atom attached to the carbonyl group, the stereoselectivity of nucleophilic addition follows the Cram’s rule

The most characteristic reaction of aldehydes and ketones is nucleophilic addition to the carbon-oxygen double bond

Many other pairs of reagents that form cabocations (orcarbocationlike species) may be used as well

No addition of bromine No oxidation No hydroation Slow addition at high temperature and pressure

11.15A Ethers by Intermolecular Dehydration of Alcohols

Acid-Catalyzed hydration of Alkenes Oxymercuration-Demeruration Hydroboration-Oxidation