Three-Component Stereoselective Enzymatic Synthesis of Amino-Diols and Amino-Polyols

Recent advances in biocatalytic C-N bond-forming reactions

Molecules containing C-N bonds are of paramount importance in a diverse array of organic-based materials, natural products, pharmaceutical compounds, and agricultural chemicals. Biocatalytic C-N bond-forming reactions represent powerful strategies for producing these valuable targets, and their significance in the field of synthetic chemistry has steadily increased over the past decade. In this review, we provide a concise overview of recent advancements in the development of C-N bond-forming enzymes, with a particular emphasis on the inherent chemistry involved in these enzymatic processes. Overall, these enzymatic systems have proven their potential in addressing long-standing challenges in traditional small-molecule catalysis.

Biocatalytic Cascades toward Iminosugar Scaffolds Reveal Promiscuous Activity of Shikimate Dehydrogenases

Iminosugar scaffolds are highly sought-after pharmaceutical targets, but their chemical synthesis is lengthy and can suffer from poor scalability and purification. Here we report protecting-group-free chemoenzymatic and biocatalytic cascades to synthesize iminosugars from sugar-derived aminopolyols in two steps. Using galactose oxidase variant F₂ followed by a chemical or enzymatic reduction provided an efficient one-pot route to these targets, with product formation >70%. Key to success of this strategy was the application of genome mining, which identified bacterial shikimate dehydrogenases as promiscuous iminosugar reductases. The cell-free protocols allowed for isolation of highly polar iminosugar products from biotransformations in a single step through development of a gradient-elution cation exchange purification. The two-step pathway provides a short synthetic route that can be used as a cell-free platform for broader iminosugar synthesis.