There are three fundamental pieces of a chemical reaction: the starting material(s), the reagent(s) and the product(s). Given two of the three you should be able to determine the third. The following sets of drill questions will test your knowledge of organic synthesis.
Alcohols and Alkyl Halides: SN Rxns
Alkenes: Elimination Rxns
Alkenes: Addition Rxns
Alkynes
Alkadienes
Arenes
Electrophilic Aromatic Substitution
Organometallics
Alcohols
Ethers and Epoxides
Aldehydes and Ketones
Enols and Enolates
Carboxylic Acids
Carboxlic Acid Derivatives
Ester Enolates
Amines
Aryl Halides
Phenols