The Design and Synthesis of Biomimetic Receptors and Catalysts

Applications of synthetic molecular receptors in selective organic transformations are discussed. Previous studies demonstrated that organic guests are selectively bound by rigid molecules in which carboxylate derivatives converge to form well-defined molecular clefts. The present account illustrates that these environments are also well suited for selective organic transformations. For example, a new class of peracids derived from the molecular receptors shows a high degree of cis/trans selectivity in oldfin epoxidation reactions. The origins of the selectivity are outlined and these and related to proposals concerning the transition structure for oxygen transfers. In addition, compounds in which carboxylic acids are embedded in chiral microenvironments are discussed with special attention given to stereoelectronic effects at carboxylate oxygens during proton transfer reactions.