LongLarf

Nature Catalysis, Published online: 27 August 2024; doi:10.1038/s41929-024-01208-2

The enantioselective formation of Csp3–Csp3 bonds is still a substantial challenge in the synthesis of complex molecules. Now, a photocatalytic system has been developed for the enantioselective alkylation of α-amino Csp3−H bonds that promotes the generation of two different alkyl radicals, followed by their cross-coupling at a chiral nickel centre.

Nature Catalysis, Published online: 19 September 2024; doi:10.1038/s41929-024-01229-x

Heterologous expression of an active, metallocentre-containing nitrogenase in a non-diazotrophic host is challenging. Now, the heterologous biosynthetic pathway of Mo-nitrogenase is pieced together in Escherichia coli using genes from Azotobacter vinelandii and Methanosarcina acetivorans.

Abstract

Flavin-dependent nitroreductases are gaining attention as biocatalysts for the synthesis of pharmaceutically active compounds and their precursors. Here, we examined a panel of nitroreductase-like flavoenzymes for their reductase activity towards a wide variety of aromatic and aliphatic nitro compounds, nitroolefins, and α,β-unsaturated carbonyl compounds. Several of these flavoenzymes displayed high reductase activity and achieved excellent conversion of diverse nitroarenes, nitroolefins and α,β-unsaturated carbonyl compounds, accomplishing good product yields in semi-preparative scale reactions (up to 97%). In addition to the catalytic promiscuity of several of these flavoenzymes, being able to perform the reduction of nitro groups (nitroreductase activity) as well as C=C groups (ene-reductase activity), this study also revealed that some flavoenzymes exhibit high chemo-, regio- and/or enantioselectivity, making them attractive enzymes for use in organic synthesis.

Nature Chemical Biology, Published online: 16 August 2024; doi:10.1038/s41589-024-01707-0

Boron is a common element found in various minerals; however, it is not used in life-creating machinery in nature. In a new study, boron enzymes have been created by introducing a boronic acid-containing non-canonical amino acid into an artificial enzyme scaffold. Further development via directed evolution enabled the selection of new-to-nature stereoselective chemistry.

Publication date: 8 August 2024

Source: Chem, Volume 10, Issue 8

Author(s): Zhi Zou, Bradley Higginson, Thomas R. Ward

Synthesis
DOI: 10.1055/s-0043-1775377

The prominence of saturated N-heterocycle motifs in pharmaceuticals is undeniable. Challenges associated with the alkylation of saturated N-heterocycle scaffolds to efficiently access new drug analogues are hampered by synthetically laborious routes. Stereocontrolled alkyl-substitutions onto saturated N-heterocycles are particularly difficult to access in high yields by traditional synthetic methods. Alternatively, C–H bond functionalization provides a new and powerful synthetic avenue by directly and selectively functionalizing/alkylating/ arylating the abundantly available C–H bonds of saturated N-heterocycles. This review highlights complementary methods for directly activating and functionalizing C–H bonds of saturated N-heterocycles chemo-, regio-, and or stereoselectively to access alkylated products. This synthetic challenge has required catalyst development to access useful N-heterocyclic building blocks or for late-stage functionalization. Early transition metal, late transition metal, photoredox, and electrochemical methods are discussed. The selective functionalization of α, β, and γ C–H bonds to form new C–C, C–N, C–O, and C–B bonds is presented.1 Introduction2 Early Transition Metal Catalyzed α-Alkylation3 Late Transition Metal Catalyzed α-Functionalization4 Photoredox-Catalyzed α-Functionalization5 Electrochemical α-Functionalization6 C–H Functionalization of β and γ C–H Bonds7 Conclusions/Outlook
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