Chemical mediators are key compounds for controlling symbiotic interactions in the environment. Here, we disclose a fully stereoselective total synthesis of the algae differentiation factor (-)-thallusin that utilizes sophisticated 6-endo-cyclization chemistry and effective late-stage sp -sp -couplings using non-toxic reagents. An EC of 4.8 pM was determined by quantitative phenotype profiling in the green seaweed Ulva mutabilis (Chlorophyte), underscoring this potent mediator's enormous, pan-species bioactivity produced by symbiotic bacteria. SAR investigations indicate that (-)-thallusin triggers at least two different pathways in Ulva that may be separated by chemical editing of the mediator compound structure.
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http://dx.doi.org/10.1002/anie.202206746 | DOI Listing |
J Am Chem Soc
January 2025
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
Direct cross-coupling reactions between two similar unactivated partners are challenging but constitute a powerful strategy for the creation of new carbon-carbon bonds in organic synthesis. [4]Dendralenes are a class of acyclic branched conjugated oligoenes with great synthetic potential for the rapid generation of structural complexity, yet the chemistry of [4]dendralenes remains an unexplored field due to their limited accessibility. Herein, we report a highly selective palladium-catalyzed oxidative cross-coupling of two allenes with the presence of a directing olefin in one of the allenes, enabling the facile synthesis of a broad range of functionalized [4]dendralenes in a convergent modular manner.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States.
ConspectusThe manipulation of strained rings is a powerful strategy for accessing the valuable chemical frameworks present in natural products and active pharmaceutical ingredients. Aziridines, the smallest N-containing heterocycles, have long served as building blocks for constructing more complex amine-containing scaffolds. Traditionally, the reactivity of typical aziridines has been focused on ring-opening by nucleophiles or the formation of 1,3-dipoles.
View Article and Find Full Text PDFJ Org Chem
January 2025
Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS) and Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
Described herein is our computational study to rationalize the stereoselective epimerization of α,α'--disubstituted oxolane and oxetane ketones and to the corresponding α,α'- ketones and reported in our previous total syntheses of (+)-3-()-isolaureatin () and (+)-3-()-laureatin (). Density functional theory (DFT) calculations using appropriately truncated models revealed that the α,α'- ketones are more stable than the α,α'- ketones, in very good agreement with experimental results. The computational results showed that the isomer with a longer interatomic distance between the two ring oxygen atoms was lower in energy, which suggested the presence of repulsive interactions between those oxygen atoms.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr Homi Bhabha Road, Pune-411008, India.
We report the stereoselective total synthesis of kavaratamide A, a linear lipodepsipeptide from the cyanobacterium (collected in Kavaratti, India), and its unnatural C25-epimer. The convergent approach employs Keck asymmetric allylation to construct the chiral β-hydroxy carboxylic acid fragment [(3)-HDA; 3-hydroxydecanoic acid], while the peptide unit was assembled from L-Val, -Me-L-Ala, ()-Hiva, and ()-Pr--Me-pyr using well-orchestrated coupling methods to prevent racemization. Modifications to the Keck allylation conditions enabled the synthesis of the C25-epimer with good yield.
View Article and Find Full Text PDFCarbohydr Res
March 2025
M. M. Shemyakin-Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, GSP-7, Ulitsa Miklukho-Maklaya, 117997, Moscow, Russian Federation. Electronic address:
A total chemical synthesis of spacer-armed Forssman pentasaccharide is reported. The choice of the 2(donor) + 3(acceptor) block scheme, the optimal combination of a limited number of simple protecting groups and the sequence of deprotection steps allowed to achieve the high yield and stereoselectivity of glycosylation and to avoid losses during deprotection. The target pentasaccharide was obtained in a 10-mg scale.
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