A Matteson Homologation‐Based Synthesis of Doliculide and Derivatives

Synthesis and biological evaluation of moiramide B derivatives

Moiramide B is a peptide-polyketide hybrid with a bacterial origin and interesting antibiotic activity. Besides its structurally conserved peptide part, it contains a highly variable fatty acid side chain. We modified this part of the molecule by introducing a terminal alkyne, and we then subjected it to click reactions and Sonogashira couplings. This provided a library of moiramide B derivatives with high and selective in vivo activities against S. aureus.

Chemical Ligation-Mediated Total Synthesis of Corramycin

The ligation-mediated total synthesis of corramycin, a myxobacterial natural product of the strain Corallococcus coralloides, is presented. The synthetic strategy included using two consecutive chemical ligations for a modular and efficient preparation. Finally, the synthesis employed a Ser/Thr ligation (STL) at a new ligation site combined with classical fragment coupling. This study provides the total synthesis of corramycin and enhances the preparative toolbox of STL in organic synthesis.

Synthesis and Late-Stage Modification of (-)-Doliculide Derivatives Using Matteson's Homologation Approach

(-)-Doliculide, a marine cyclodepsipeptide derived from the Japanese sea hare, Dolabella auricularia, exhibits potent cytotoxic properties, sparking interest in the field of synthetic chemistry. It is comprised of a peptide segment and a polyketide moiety, rendering it amenable to Matteson's homologation methodology. This technique facilitates the diversification of the distinctive polyketide side chain, thereby permitting the introduction of functional groups in late stages for modifications of the derived compounds and studies on structure-activity relationships.

Matteson Homologation-Based Total Synthesis of Meliponamycin A

The first total synthesis of meliponamycin A, an antimicrobial cyclodepsipeptide isolated from Streptomyces, is reported. Two key building blocks, the substituted tetrahydropyranyl side chain and an azido analogue of protected β-hydroxyleucine, were constructed via iterative Matteson homologations. A fragment coupling of a tetrapeptide, a depsidipeptide building block, macrocyclization, Staudinger reduction, and N-acylation are further steps in the synthesis.

Stereoselective Synthesis of Secondary and Tertiary Boronic Esters via Matteson Homologation

Matteson homologations of chiral boronic esters with lithium dichlorocarbenoids and various nucleophiles proved to be a useful method for the synthesis of functionalized polyketides in a highly stereoselective fashion. Via repeated homologation steps, only 1,2-anti- and 1,3-syn-configured products were obtained. Homologation with substituted carbenoids followed by reaction with carbon nucleophiles resulted in configurationally inverted products and tertiary boronic esters in a highly stereoselective fashion. This approach significantly expands the potential of the Matteson reaction.

Isomerization-Free Matteson Homologations of Substituted Allylboronic Esters

Substituted allyl derivatives with an internal double bond can be homologated under standard conditions via a 1,2-shift, whereas allylboronic esters with terminal double bonds can also be homologated via a SN' reaction. This allyl isomerization is catalyzed by ZnCl2 and can be suppressed by omitting ZnCl2 during the formation of α-chloroboronic ester. However, in the second step with Grignard reagents, ZnCl2 was added to suppress side reactions of the product formed.

Total synthesis and biological evaluation of histone deacetylase inhibitor WF-3161

A novel synthesis of the naturally occurring HDAC inhibitor WF-3161 is described. Key steps include the Matteson homologation to generate the stereogenic centres in the side chain, and Pd-catalysed C-H functionalisation to connect the side chain to the peptide backbone. WF-3161 was found to be highly selective for HDAC1, whereas no activity was observed towards HDAC6. High activity was also found against the cancer cell line HL-60.

Marine natural products

Covering: January to December 2021This review covers the literature published in 2021 for marine natural products (MNPs), with 736 citations (724 for the period January to December 2021) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1425 in 416 papers for 2021), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. An analysis of the number of authors, their affiliations, domestic and international collection locations, focus of MNP studies, citation metrics and journal choices is discussed.

Depsipeptides Targeting Tumor Cells: Milestones from In Vitro to Clinical Trials

Cancer is currently considered one of the most threatening diseases worldwide. Diet could be one of the factors that can be enhanced to comprehensively address a cancer patient's condition. Unfortunately, most molecules capable of targeting cancer cells are found in uncommon food sources. Among them, depsipeptides have emerged as one of the most reliable choices for cancer treatment. These cyclic amino acid oligomers, with one or more subunits replaced by a hydroxylated carboxylic acid resulting in one lactone bond in a core ring, have broadly proven their cancer-targeting efficacy, some even reaching clinical trials and being commercialized as "anticancer" drugs. This review aimed to describe these depsipeptides, their reported amino acid sequences, determined structure, and the specific mechanism by which they target tumor cells including apoptosis, oncosis, and elastase inhibition, among others. Furthermore, we have delved into state-of-the-art in vivo and clinical trials, current methods for purification and synthesis, and the recognized disadvantages of these molecules. The information collated in this review can help researchers decide whether these molecules should be incorporated into functional foods in the near future.

Stereoselective Synthesis of a Protected Side Chain of Callipeltin A

Matteson homologations of chiral boronic esters proved to be an excellent tool for the synthesis of highly functionalized amino and hydroxy acid residues. This method provides straightforward stereoselective access to the side chain of callipeltin A, a natural marine product with interesting biological activities. Furthermore, this protocol should allow for variations in the substitution pattern in future SAR studies, simply by choosing suitable nucleophiles during the homologation steps.

Application of Vinyl Nucleophiles in Matteson Homologations

The Matteson homologation with vinyl nucleophiles was found to be a versatile tool for the synthesis of highly substituted and functionalized allyl boronic esters. High yields and stereoselectivities are obtained with sterically demanding alkyl boronic esters and/or Grignard reagents. With the application of such vinyl Matteson homologations, the polyketide fragment of lagunamide B is synthesized.

Stereoselective Synthesis of a Protected Side Chain of Meliponamycin A

The Matteson homologation was found to be a versatile tool for the construction of the linear polyketide side chain of meliponamycin and related compounds in only four steps. The ester dienolate version of this reaction allowed the introduction of the unsaturated ester moiety in a highly stereoselective fashion. Boronate oxidation/deoxygenation and Sharpless dihydroxylation are additional key steps in the stereoselective construction of this highly functionalized tetrahydropyran ring system, which is characteristic of this substance class.