Immobilization of organic catalysts: When, why, and how

This review article is divided in two parts. In the first part (Sections 2 and 3) selected examples of the publications that appeared in the literature in the period 2003-2005 in the field of immobilized organic catalysis are presented. When appropriate, the results of these publications are compared to those reported earlier and already discussed in a previous review article (see ref.([4])). On the basis of this survey, in Section 4 some general considerations about when and why a supported version of an organic catalyst is worth developing are proposed. In Section 4 a list of suggestions about how the process of immobilization should be carried out is also included, taking into account several factors such as the properties of the catalyst, the nature of the support, and the mode of connection of the catalyst to the support. 1 Introduction 2 Achiral Organic Catalysts 2.1 Catalysts for Oxidation Reactions 2.2 Lewis Base Catalysts 2.3 Acid Catalysts 2.4 Thiazolium Salts 2.5 Miscellaneous Catalysts 2.6 Bifunctional Catalysts 3 Chiral Organic Catalysts 3.1 Catalysts for Oxidation Reactions 3.2 Lewis Base Catalysts 3.3 Catalysts Derived from Cinchona Alkaloids 3.4 Catalysts Derived from Amino Acids 4 A Short Discussion on the Practical Aspects of Catalyst Immobilization 4.1 When? 4.2 Why? 4.3 How? 5 Conclusions