A number of cyclic derivatives of 3-amino-2,4-dihydroxybutanoic acid are known in the literature but they are often prepared from other cyclic precursors. This study showed that the title compound too may serve as a convenient substrate for cyclization reactions. Using orthogonally-protected linear derivatives, regioselective cyclizations were performed, leading to original and highly-functionalized γ-lactones, oxazolidinones, oxazolines and aziridines. In these reactions a key role was played by the C3 nitrogen group function, while the C2 alcohol function showed no propensity for participation in cyclization reactions.
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http://dx.doi.org/10.1039/c6ob02759h | DOI Listing |
J Org Chem
December 2024
College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, Zhejiang, China.
In this work, a switchable synthesis of β-ketosulfone and α-chloroketone through a radical difunctionalization of alkenes is reported. The transformation works well under iron peroxo species/photoredox dual catalysis and an open-flask atmosphere, and the reaction is highlighted with good yields and a broad reaction scope. Mechanism studies show that the reaction is initiated by a formal [4 + 2] cyclization of the sulfonyl radical in a regioselective manner.
View Article and Find Full Text PDFACS Catal
December 2024
Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
Lanthipeptides are ribosomally synthesized and post-translationally modified peptides (RiPPs) characterized by the presence of thioether cross-links called lanthionine and methyllanthionine, formed by dehydration of Ser/Thr residues and Michael-type addition of Cys side chains onto the resulting dehydroamino acids. Class II lanthipeptide synthetases are bifunctional enzymes responsible for both steps, thus generating macrocyclic natural products. ProcM is part of a group of class II lanthipeptide synthetases that are known for their remarkable substrate tolerance, having large numbers of natural substrates with highly diverse peptide sequences.
View Article and Find Full Text PDFOrg Chem Front
December 2024
Department of Chemistry, University of Basel St Johanns-Ring 19 Basel 4056 Switzerland https://www.chemie1.unibas.ch/Bmayor/.
This work explores the use of a cross-shaped organic framework that is used as a template for the investigation of multi-functionalized chromophores. We report the design and synthesis of a universal cross-shaped building block bearing two bromines and two iodines on its peripheral positions. The template can be synthesized on a gram scale in a five-step reaction comprising an oxidative homo-coupling macro-cyclization.
View Article and Find Full Text PDFOrg Lett
December 2024
Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Innovative Drug Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China.
We here report an efficient DNA-compatible furan-thiol-amine reaction for macrocyclization and late-stage amine transformation. This reaction, conducted under mild conditions, enables the facile cyclization of DNA-conjugated linear peptides into thiopyrrole-grafted macrocycles regardless of ring size or side-chain modification with good to excellent conversion yields. Additionally, this strategy was employed for the late-stage transformation of terminal amines, serving as critical intermediates in the construction of DNA-encoded peptide libraries.
View Article and Find Full Text PDFJ Org Chem
December 2024
Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China.
A palladium-catalyzed asymmetric chlorocyclization of 1,6-enynes has been described. Controlling the chloride ion concentration in the system by substrate design is the key to achieving asymmetric chlorinated cyclization. In the presence of Pd(PhCN)Cl and chiral phosphoramidite ligands, the reaction accesses diverse chiral ()-α-chloromethylene-γ-butyrolactams with excellent selectivity and enantioselectivity.
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