Classes of Mechanisms

  1. Almost all mechanisms you will encounter fall into one of ten basic mechanistic classes; some will be combinations of two or three of the basic classes. If these fundamental processes can be identified, then a mechanism can be written by merely matching each reaction partner to its role in the fundamental type.

  2. The ten principal classes of reaction mechanism are:

    1. Radical substitution (SH)

    2. Radical addition (AH)

    3. Bimolecular nucleophilic substitution (SN2)

    4. Unimolecular nucleophilic substitution/elimination (SN1/E1)

    5. Bimolecular elimination (E2)

    6. Electrophilic addition (AE)

    7. Electrophilic substitution (SE)

    8. Nucleophilic addition (AN)

    9. Nucleophilic acyl substitution (SNAc)

    10. Pericyclic reorganizations

  3. Write all steps of one example of each kind of reaction. Use specific molecules and specific reagents, including solvent, and make each of these reaction constituents representative. That is, use substrates that really undergo the reaction, solvents that especially facilitate it, and so on.

  4. Return to the reactions given in previous sections (Problems 1 - 15). Identify the fundamental mechanistic type(s) involved in each reaction.

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