A chemoenzymatic and enantioselective total synthesis of the resorcylic acid lactone L-783,290, the trans-isomer of L-783,277

Natural and Synthetic Lactones Possessing Antitumor Activities

Cancer is one of the leading causes of death globally, accounting for an estimated 8 million deaths each year. As a result, there have been urgent unmet medical needs to discover novel oncology drugs. Natural and synthetic lactones have a broad spectrum of biological uses including anti-tumor, anti-helminthic, anti-microbial, and anti-inflammatory activities. Particularly, several natural and synthetic lactones have emerged as anti-cancer agents over the past decades. In this review, we address natural and synthetic lactones focusing on their anti-tumor activities and synthetic routes. Moreover, we aim to highlight our journey towards chemical modification and biological evaluation of a resorcylic acid lactone, L-783277 (4). We anticipate that utilization of the natural and synthetic lactones as novel scaffolds would benefit the process of oncology drug discovery campaigns based on natural products.

Asymmetric total syntheses of naturally occurring α,β-enone-containing RALs, L-783290 and L-783277 through intramolecular base-mediated macrolactonization reaction

Asymmetric total synthesis of two naturally occurring α,β-enone containing RALs, L-783290 and L-783277 is described in this article. An E-selective Horner-Wadsworth-Emmons (HWE) olefination was used as a key reaction to construct the C7'-C8' olefinic unsaturation in L-783290. An enantiopure alkyne addition to the aldehyde followed by Z-selective partial reduction was employed to construct the C7'-C8' olefinic unsaturation in L-783277. Biomimetic lactonization reaction was used to construct the macrolactone core in both the target molecules.

The Application of Dioxygenase-Based Chemoenzymatic Processes to the Total Synthesis of Natural Products

This Minireview describes the exploitation of certain enzymatically derived, readily accessible, and enantiomerically pure cis-1,2-dihydrocatechols as starting materials in the chemical synthesis of a range of biologically active natural products, most notably sesquiterpenoids and alkaloids.

Benefits of Unconventional Methods in the Total Synthesis of Natural Products

This article provides a survey of four "unconventional" methods employed in the synthesis of natural products in the Hudlicky group. The utility of flash vacuum pyrolysis is highlighted by examples of many natural products attained via vinylcyclopropane-cyclopentene rearrangement and its heterocyclic variants. Preparative organic electrochemistry was used in oxidations and reductions with levels of selectivity unattainable by conventional methods. Yeast reduction of ketoesters was featured in the total synthesis of pyrrolizidine alkaloids. Finally, the use of toluene dioxygenase-mediated dihydroxylations in enantioselective synthesis of natural products concludes this presentation. Recently, synthesized targets in the period 2010-2019 are listed in the accompanying table. The results of research from the Hudlicky group are placed in appropriate context with the work of others, and a detailed guide to the current literature is provided.

Resorcylic acid lactones (RALs) and their structural congeners: recent advances in their biosynthesis, chemical synthesis and biology

Resorcylic acid lactones (RALs) are naturally occurring 14-membered macrolactones that constitute a class of polyketides derived from fungal metabolites and that possess significant and promising biological activity.

Total Syntheses of the Resorcylic Acid Lactones Paecilomycin F and Cochliomycin C Using an Intramolecular Loh-Type α-Allylation Reaction for Macrolide Formation

Subjection of the resorcylic ester 16 to a Nozaki-Hiyama-Kishi reaction afforded the 12-membered lactone 17, while treatment of it under the Loh-type α-allylation conditions using indium metal gave the isomeric, 14-membered macrolide 18. Compound 18 was readily elaborated to the resorcylic acid lactone type natural products paecilomycin F and cochliomycin C.

Total syntheses of the resorcylic acid lactone neocosmosin A and its enantiomer

A total synthesis of the structure, 1, assigned to the recently reported resorcylic acid lactone (RAL) neocosmosin A has been established. Olefin-cross metathesis, ring-closing metathesis, palladium-catalyzed Meinwald rearrangement, and Mitsunobu esterification reactions were used as key steps. A late-stage and simple modification to the reaction sequence also provided compound ent-1 that, in fact, represents the true structure of the natural product.

Modular total syntheses of the marine-derived resorcylic Acid lactones cochliomycins a and B using a late-stage nozaki-hiyama-kishi macrocyclization reaction

The natural products cochliomycin A (1) and cochliomycin B (2), two resorcylic acid lactones obtained from marine sources, have been prepared in a concise and stereocontrolled manner from the readily accessible building blocks 4-6. Olefin cross-metathesis, trans-esterification and Nozaki-Hiyama-Kishi (NHK) macrocyclization reactions were employed in the key steps. Hydrolysis of the immediate precursor to cochliomycin B affords the resorcylic acid lactone zeaenol (24).