Multiple stereodifferentiation

A compilation of different catalytic stereoselective processes seems unnecessary for the purpose of a classification of the stereoselective syntheses. However, a few examples of some less frequently encountered catalytic kinetic resolutions and chiral catalyst mediated multiple stereodifferentiating reactions will be presented in Fig. 8. 

The multiplicative combination of two effects is known as double stereodifferentiation 62. One problem is to achieve high asymmetric induction in the catalytic hydrogenation of 2-acetylamino-3-phenylpropenoic acid63. 

Olefin polymerization is not a simple single-step olefin insertion process it involves complex kinetics and multiple equilibria. Insertion is preceded by olefin complexation (Scheme 7.2a) or olefin complexation coupled with counterion displacement (Scheme 7.2b). In view of this complexity, how can the use of barrier differences be justified The use of barrier height differences arises from the Curtin-Hammett principle. The Curtin-Hammett principle is a kinetic analysis that describes product distributions for reactions involving a pair of equilibrating reactants or intermediates, each capable of forming a product. The stereodifferentiation of general isotactic polymerization can be... 

---