Tandem Ring-Closing/Cross-Metathesis Approach for the Synthesis of Synargentolide B and Its Stereoisomers

Versatile Synthesis of Organic Compounds Derived from Ascorbic Acid

:

Ascorbic acid, also known as Vitamin C, is the most important vitamin observed in diverse food. Ascorbic acid has various applications in several fields. Studies have depicted that in organic synthesis, it can be used as a mediator or substrate. The derivatives of ascorbic acid have been found to possess numerous biological activities. In this review, we report the important derivatives of ascorbic acid, which have significant biological activities. Various studies are considered in this review to prove its wide range of availability.

Recent Advances in the Stereoselective Total Synthesis of Natural Pyranones Having Long Side Chains

Pyranone natural products have attracted great attention in recent years from chemists and biologists due to their fascinating stereoisomeric structural features and impressive bioactivities. A large number of stereoselective total syntheses of these compounds have been described in the literature. The natural pyranones with long side chains have recently received significant importance in the synthetic field. In the present article, we aim to review the modern progress of the stereoselective total syntheses of these natural pyranones containing long-chain substituents.

First stereoselective total synthesis of brevipolide M

The first stereoselective total synthesis of a cytotoxic brevipolide M, which shares a pyrone framework bearing a tetrahydrofuran moiety and a cinnamate group with the readily available (-)-DET, is described. The key steps involved in the synthesis are the epoxide-opening, Brown's allylation, and the RCM reaction to install an α,β-unsaturated lactone ring and the inversion of the C-6' stereogenic hydroxyl group using the Mitsunobu reaction.

Identification and Synthesis of Mycalol Analogues with Improved Potency against Anaplastic Thyroid Carcinoma Cell Lines

The marine metabolite mycalol (1) has a specific inhibitory activity on cells of anaplastic thyroid carcinoma (ATC), a very aggressive and rare cancer that does not have effective conventional therapy. In this study, we describe six new related analogues (2-7) that differ in the length of the terminal alkyl residue and the presence of acetate or 3S-hydroxybutyrate (3S)-3HB as a substituent at C-19. Despite the structural analogies, some of the new members were significantly more cytotoxic than 1 on cell lines derived from human ATC. Structures inclusive of the 2'R,3R,4S,7R,8S,19R absolute configuration were assigned to 2-7 on the basis of detailed spectroscopic analysis, synthesis of different isomers, and application of ECD and Mosher's methods. This work led to the identification of mycalol-578 (3) as the most potent analogue, with an IC₅₀ of 2.3 μM on FRO cells.

Total Synthesis of Cryptocaryol A by Enantioselective Iridium-Catalyzed Alcohol C-H Allylation

The polyketide natural product cryptocaryol A is prepared in 8 steps via iridium catalyzed enantioselective diol double C-H allylation, which directly generates an acetate-based triketide stereodiad. In 4 previously reported total syntheses, 17-28 steps were required.

Total synthesis and structural revision of mycalol, an anticancer natural product from the marine source

The total synthesis of an anticancer (anaplastic thyroid) natural lipid mycalol has been accomplished for the first time. Synthesis of originally proposed structure necessitated the revision of structure in which the position of acetate group moved from C20 to C19 and a change in stereochemistry of the glycerol unit.

First total synthesis of cryptopyranmoscatone A2 from d-ribose

The first total synthesis of a naturally occurring styryl lactone, cryptopyranmoscatone A2 has been achieved from inexpensive and highly abundant d-ribose.

The first total synthesis of (+)-goniothalesacetate and syntheses of (+)-altholactone, (+)-gonioheptolide A, and (−)-goniofupyrone by an asymmetric acetate aldol approach

First stereoselective total synthesis of (+)-goniothalesacetate and total synthesis of (+)-altholactone, (+)-gonioheptolide A, and (−)-goniofupyrone have been achieved.