Advances in catalytic and protecting-group-free total synthesis of natural products: a recent update

Aconitine and its derivatives: bioactivities, structure-activity relationships and preliminary molecular mechanisms

Aconitine (AC), which is the primary bioactive diterpene alkaloid derived from Aconitum L plants, have attracted considerable interest due to its unique structural feature. Additionally, AC demonstrates a range of biological activities, such as its ability to enhance cardiac function, inhibit tumor growth, reduce inflammation, and provide analgesic effects. However, the structure-activity relationships of AC are remain unclear. A clear understanding of these relationships is indeed critical in developing effective biomedical applications with AC. In line with these challenges, this paper summarized the structural characteristics of AC and relevant functional and bioactive properties and the structure-activity relationships presented in biomedical applications. The primary temporal scope of this review was established as the period spanning from 2010 to 2023. Subsequently, the objective of this review was to provide a comprehensive understanding of the specific action mechanism of AC, while also exploring potential novel applications of AC derivatives in the biomedical field, drawing upon their structural characteristics. In conclusion, this review has provided a comprehensive analysis of the challenges and prospects associated with AC in the elucidation of structure-bioactivity relationships. Furthermore, the importance of exploring modern biotechnology approaches to enhance the potential biomedical applications of AC has been emphasized.

Chiral Pool Meets Chiral Catalysis: Eight-Step Convergent Total Synthesis of Anticancer Natural Lipid Mycalol

An exemplary blend of chiral pool with chiral catalysis is exhibited in an eight-step (longest) convergent asymmetric total synthesis of mycalol, which is a promising anticancer natural lipid from a marine source. The polyhydroxy lipid is constructed by using four blocks, and two of which are derived from the chiral pool (d-mannitol and d-gluconolactone) and the other two by chiral catalysis (Sharpless epoxidation and Keck allylation). Alkylation and metathesis were used to knit the blocks in an excellent display of a modular convergent eight-step synthesis. The modular excess will enable rapid analogue generation as revealed by the convenient synthesis of 4-epi-mycalol similarly in an eight-step sequence.

Digitization and validation of a chemical synthesis literature database in the ChemPU

Despite huge potential, automation of synthetic chemistry has only made incremental progress over the past few decades. We present an automatically executable chemical reaction database of 100 molecules representative of the range of reactions found in contemporary organic synthesis. These reactions include transition metal–catalyzed coupling reactions, heterocycle formations, functional group interconversions, and multicomponent reactions. The chemical reaction codes or χDLs for the reactions have been stored in a database for version control, validation, collaboration, and data mining. Of these syntheses, more than 50 entries from the database have been downloaded and robotically run in seven modular ChemPU’s with yields and purities comparable to those achieved by an expert chemist. We also demonstrate the automatic purification of a range of compounds using a chromatography module seamlessly coupled to the platform and programmed with the same language.

Chemoinformatic Exploration of "Bioinspired Metabolomes" Illuminates Diacetyl Assembly Pathways Toward Nesteretal A-Like Cage Molecules

An appealing and challenging cage structure along with an unusual biosynthetic pathway prompted us to explore an expeditious bioinspired one-pot total synthesis of nesteretal A. An unconventional strategy was chosen, and a cascade reaction starting from diacetyl was studied. Under organocatalytic conditions mimicking an aldolase, nesteretal A and a related cage analogue were anticipated by in silico metabolization, detected, targeted, and characterized.

Concise Stereoselective Synthesis of β-Hydroxy-γ-lactones: (4R,5R)-4-Hydroxy-γ-decalactone from the Japanese Orange Fly and Enantiomers of Arachnid Harvestmen Isolates

The naturally occurring (4R,5R)-4-hydroxy-γ-decalactone from the Japanese orange fly and the antipode of (4S,5R)-4-hydroxy-γ-dodecalactone from the harvestmen arachnid and their stereoisomers are synthesized from the chiral pool material d-glucono-δ-lactone in a few steps. The one-pot conversion of the latter to γ-vinyl-β-hydroxy-γ-lactone, cross-metathesis with requisite olefin, and hydrogenation enabled the synthesis of syn-lactones in just a two-pot operation. An additional efficient Pd-catalyzed allylic isomerization of γ-vinyl-β-hydroxy-γ-lactone led to the anti-lactones in high yields.

Synthesis of the Hexahydropyrrolo-[3,2-c]-quinoline Core Structure and Strategies for Further Elaboration to Martinelline, Martinellic Acid, Incargranine B, and Seneciobipyrrolidine

Natural products are rich sources of interesting scaffolds possessing a plethora of biological activity. With the isolation of the martinella alkaloids in 1995, namely martinelline and martinellic acid, the pyrrolo[3,2-c]quinoline scaffold was discovered. Since then, this scaffold has been found in two additional natural products, viz. incargranine B and seneciobipyrrolidine. These natural products have attracted attention from synthetic chemists both due to the interesting scaffold they contain, but also due to the biological activity they possess. This review highlights the synthetic efforts made for the preparation of these alkaloids and formation of analogues with interesting biological activity.