Part I: Development of direct asymmetric aldol reactions mediated by primary amino acid-derived organocatalysts Part II: Exploring DNA-cleaving activities of Varacin B and Varacin C

Abstract

A series of amino organocatalysts were derived from primary amino acids in part I. The direct asymmetric aldol reactions catalyzed by these organocatalysts were investigated in the presence of water. It was found that hydrophobic primary amino organocatalysts, such as L-tryptophan and O-TBS-L-threonine are efficient for the aldol reactions in water. The asymmetric organocatalytic aldol reactions employing hydroxyacetone as a donor offer an easy access to synthetically versatile 1,2-diols. Natural products varacin B and varacin C salts were synthesized; and their DNA-cleaving functionalities under acidic or UV-promoting conditions were studied in part II. It was found that both varacin B and varacin C displayed good DNA cleavage activities, and such compounds represent promising structural motifs for the future development of anti-cancer therapeutics.