The Design and Synthesis of Phenylcyclopropane-Based Secondary Amine Catalysts and Their Applications in Asymmetric Reactions

Abstract

Most chiral secondary amine catalysts are usually synthesized from chiral amino acids and their derivatives. On the other hand, the amine catalysts based on a binaphthyl backbone have previously been developed, and show unique chemo- and stereoselectivity in some asymmetric reactions. In spite of their utility, however, the applications of binaphthyl-based amines in asymmetric reactions are still rare due to their synthetic inefficiency. In this context, we designed amine catalysts possessing a phenylcyclopropane scaffold as a novel chiral motif. The novel catalysts could be synthesized easily and construct a similar chiral environment to that of binaphthyl-based amine catalysts. In addition, the phenylcyclopropane-based amino sulfonamide was found to be an effective catalyst for the syn-selective Mannich reaction and conjugate addition using alkynyl Z-ketimines.