Total synthesis of nitropyrrolins A, B, and D

Marine Pyrrole Alkaloids

Nitrogen heterocycles are essential parts of the chemical machinery of life and often reveal intriguing structures. They are not only widespread in terrestrial habitats but can also frequently be found as natural products in the marine environment. This review highlights the important class of marine pyrrole alkaloids, well-known for their diverse biological activities. A broad overview of the marine pyrrole alkaloids with a focus on their isolation, biological activities, chemical synthesis, and derivatization covering the decade from 2010 to 2020 is provided. With relevant structural subclasses categorized, this review shall provide a clear and timely synopsis of this area.

Cross-coupling reactions towards the synthesis of natural products

Cross-coupling reactions are powerful synthetic tools for the formation of remarkable building blocks of many naturally occurring molecules, polymers and biologically active compounds. These reactions have brought potent transformations in chemical and pharmaceutical disciplines. In this review, we have focused on the use of cross-coupling reactions such as Suzuki, Negishi, Heck, Sonogashira and Stille in the total synthesis of some natural products of recent years (2016-2020). A short introduction of mentioned cross-coupling reactions along with highlighted aspects of natural products has been stated in separate sections. Additionally, few examples of natural products via incorporation of more than one type of cross-coupling reaction have also been added to demonstrate the importance of these reactions in organic synthesis.

Recent progress in the total synthesis of pyrrole-containing natural products (2011–2020)

This review discusses total syntheses of pyrrole-containing natural products over the last ten years, highlighting recent advances in the chemistry of pyrroles in the context of their innate reactivity, and their preparation in complex settings.

Reactivity of 2-Nitropyrrole Systems: Development of Improved Synthetic Approaches to Nitropyrrole Natural Products

Fundamental study of the reactivity of 2-nitropyrrole systems has enabled the identification of effective methods for incorporation of this unusual motif into advanced natural product frameworks. The presence of electron-rich pyrrole N-protecting groups (BOM, Boz) was demonstrated to enable a variety of previously unsuccessful palladium-mediated cross-couplings to be carried out in high yield. Based on this foundation, a series of regio- and stereoselective synthetic routes toward the nitropyrrolin and heronapyrrole families of natural products was developed by our group (G1-3). A full account of the strategic evolution of these approaches is reported here, highlighting the details of the setbacks encountered and eventual successes achieved en route, including the total synthesis of heronapyrrole B. The fundamental studies and completed total syntheses provide general access to the bioactive 2-nitropyrrole natural product manifold and also establish practical and efficient methods for preparation and elaboration of the medicinally relevant 2-nitropyrrole motif.

Marine natural products

Covering: 2016. Previous review: Nat. Prod. Rep., 2017, 34, 235-294This review covers the literature published in 2016 for marine natural products (MNPs), with 757 citations (643 for the period January to December 2016) 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 (1277 in 432 papers for 2016), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included.

General Synthesis of the Nitropyrrolin Family of Natural Products via Regioselective CO2-Mediated Alkyne Hydration

The total synthesis of the 2-nitropyrrole natural products nitropyrrolins A and B and the formal synthesis of nitropyrrolin D are reported. The key 2-nitro-4-alkylpyrrole core was efficiently assembled by Sonogashira cross-coupling, with complete control of regioselectivity. An unusual carboxylative cyclization, sulfonylcarbamate formation, and base-promoted cleavage sequence enabled access to the key hydroxy ketone without affecting the protected 2-nitropyrrole unit. The total synthesis provides a general approach for preparation of the bioactive nitropyrrolin family of natural products.