Design and Synthesis of a Novel Primary Amine-Thiourea Organocatalyst Based on Unactivated C(sp3)-H Amination Reaction

Abstract

In order to apply the C-H activation strategy to the synthesis of novel organic catalysts, a novel primary amine-thiourea catalyst is designed and synthesized by using the developed inert C(sp3)-H amination method as a key step. First, using phenylalanine as the substrate and di-tert-butyl-azodicarboxylic acid as the nitrogen source, the corresponding amination products are obtained by employing the Pd-catalyzed inert C(sp3)-H amination method. Next, the chiral skeleton of 1,2-diamine privileged in organocatalysts is obtained by simple conversion. Then, a novel chiral primary amine-thiourea bifunctional organic catalyst is synthesized, whose structure is characterized by nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HRMS). The synthesized catalyst is also successfully applied to the asymmetric Michael addition reaction of isobutyraldehyde with nitroolefins. Due to the advantages of transition metal-catalyzed C-H activation, such as simplicity, high efficiency, high atomic economy, and non pre-functionalization, its application to the development of small molecular catalysts will undoubtedly make the structure of catalyst more diversified and the synthesis process more efficient.

Keywords

• c-h amination
• primary amine
• thiourea
• organic catalysis