Practical Consequences of Non-Linear Effects in Asymmetric Synthesis

The fundamental principles of non-linear effects (NLE) are reviewed. Particular emphasis is placed on the case of asymmetric amplification, since it allows one to perform useful chemistry with a non-enantiopure chiral auxiliary. A strong asymmetric depletion in a catalytic reaction may lead to an underestimation of the actual enantioselectivity of the fully resolved ligand. The study of NLE's is also proving useful as a mechanistic tool in asymmetric catalysis. Similar concepts may be extended to chiral reagents or to kinetic resolution. 1. What is a Non-Linear Effect in Asymmetric Synthesis? 2. The Conditions for Observing a Non-Linear Effect in Enantioselective Catalysis 3. Some Simple Models of NLE in Enantioselective Catalysis 4. Comparison of the Sizes of Asymmetric Amplifications 5. Rates and Non-Linear Effects in Asymmetric Catalysis 6. Non-Linear Effects Involving Chiral Reagents 7. Mechanistic Applications of Non-Linear Effects 8. Synthetic Applications 9. Concluding Remarks