Highly Modular Dipeptide-like Organocatalysts For Direct Asymmetric Aldol Reactions

In recent years, the use of amino acid catalyzed aldol reactions become popular, especially a series of peptides derived from the catalytic reaction of this type of catalyst, and achieved very good results. Small molecule peptide catalysts synthesis easily, mild conditions, environmental protection and high efficiency, and gradually more and more people’s attention. Therefore, this study based on the advantages of peptide-based catalysts, designed and synthesized dipeptide catalyst is highly adjustable.This paper has following two aspects:1. we designed and synthesized dipeptide catalyst proline, valine and benzylamine as a new class of materials with adjustable height, the structure of the catalyst by characterized 1H NMR, 13 C NMR, HRMS and other tools.2. A novel series of dipeptide-like organocatalysts have been prepared for direct asymmetric aldol reactions between various aldehydes and ketones to afford aldol products in good yields(up to 91%) and enantioselectivities(up to 88% ee) with only 1 mol% of catalyst-loading in the aqueous medium.These organocatalysts are easily synthesized from commercially available materials in multi-gram scale with high modularity in their structural and stereogenic properties.