Total Synthesis of the Proposed Structure of Marineosin A

Hypervalent Iodine-Mediated Synthesis of Steroidal 5/5-Spiroiminals

The hypervalent iodine-mediated formation of steroidal 5/5-spiroiminals and 5/5-spiroaminals from steroidal amines is presented. Under the influence of excess PhI(OAc)2 and iodine in acetonitrile at 0 °C, steroidal amines smoothly underwent cyclization to give a mixture of 5/5-spiroiminals and 5/5-spiroaminals. This reaction represents the first example of a C-H-activation-mediated formation of a spiroiminal. Presumably, the formation of 5/5-spiroiminals occurs through aminyl radical-mediated cyclization followed by amine-to-imine oxidation.

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.

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.

Bismuth as Smart Material and Its Application in the Ninth Principle of Sustainable Chemistry

This paper reports an overview of Green Chemistry and the concept of its twelve principles. This study focusses on the ninth principle of Green Chemistry, that is, catalysis. A report on catalysis, in line with its definition, background, classification, properties, and applications, is provided. The study also entails a green element called bismuth. Bismuth’s low toxicity and low cost have made researchers focus on its wide applications in catalysis. It exhibits smartness in all the catalytic activities with the highest catalytic performance among other metals.

A mild and efficient method for the synthesis of pyrroles using MIL-53(Al) as a catalyst under solvent-free sonication

A highly efficient method for the synthesis of pyrroles using MIL-53(Al) as a catalyst has been developed under solvent-free sonication. This reaction has a broad substrate scope and high yields were obtained within a short reaction time. Remarkably, no additional additives and volatile organic solvent are required for this method and the MIL-53(Al) could be recovered and reused several times without significant drop-off in catalytic activity.

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.

Recent advances on the total synthesis of alkaloids in mainland China

Alkaloids are a large family of natural products that mostly contain basic nitrogen atoms. Because of their intriguing structures and important functions, they have long been popular targets for synthetic organic chemists. China's chemists have made significant progress in the area of alkaloid synthesis over past decades. In this article, selected total syntheses of alkaloids from research groups in mainland China during the period 2011–16 are highlighted.

MarH, a Bifunctional Enzyme Involved in the Condensation and Hydroxylation Steps of the Marineosin Biosynthetic Pathway

A novel bifunctional enzyme, MarH, has been identified, and its key functional role in the marineosin biosynthesis successfully probed. MarH catalyzes (1) a condensation step between 4-methoxy-2,2'-bipyrrole-5-carboxaldehyde (MBC) and 2-undecylpyrrole (UP) to form undecylprodiginine (UPG) and (2) hydroxylation of the alkyl chain of UPG to form the (S)-23-hydroxyundecylprodiginine (HUPG), which is essential for MarG catalyzed bicyclization toward the formation of an unusual spiro-tetrahydropyran-aminal ring of marineosins. The final enigmatic steps in the marineosin biosynthesis have now been deciphered.

A green and efficient method for the synthesis of pyrroles using a deep eutectic solvent ([CholineCl][ZnCl2]3) under solvent-free sonication

A green and efficient method for Paal–Knorr pyrrole synthesis has been developed under mild conditions.