Search

In order to apply the C-H activation strategy to the development of chiral organic catalysts, two novel C3-trimethylsilyl substituted chiral proline catalysts are designed and synthesized using L-proline as the starting material and C(sp 3)-H silylation as the key step, which are applied to the asymmetric aldol reaction of p-nitrobenzaldehyde with acetone and the asymmetric Mannich reaction of imine with β-methylbutyraldehyde, respectively. Both target products can be synthesized with a good enantioselectivity. This strategy effectively enriches the means of structural modification of proline and provids a new method for the development of new silicon-containing organic catalysts.

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.