Polymer Supports in Synthesis

Abstract

Diversity-oriented synthesis (DOS) is a term used by Schreiber (S. Schreiber, Science, 2000, 287, 1964) to describe the preparation of a large variety of highly functionalized molecules in a few steps, frequently involving combinatorial methods on polymer supports. Enantioselective 1,3-dipolar cycloaddition of azomethine ylides (see S. Kanemasa, Synless, 2002, 1371–1387) with electron-deficient olefins is a reaction method that produces stereochemical diversification by generating up to four tetrahedral centers on pyrolidine rings. The biological importance of pyrrolidines has stimulated the development of diasteroselective [3+2] azomethine ylide cycloadditions (J. Longmire, B. Wang, and Y. Zhang, J. Am. Chem. Soc., 2002, 124, 413400) and enantioselective variations employing chiral catalysts (K. A. Jorgensen, Angew. Chem. Int. Ed., 2002, 41, 4236). Now, Schreiber has developed the three-component, catalytic, asymmetric [3+2] cycloaddition of azomethine ylides for application in DOS employing solid phase ...