https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Rapid improvements in sequencing and array-based platforms are resulting in a flood of diverse genome-wide data, including data from exome and whole-genome sequencing, epigenetic surveys, expression profiling of coding and noncoding RNAs, single nucleotide polymorphism (SNP) and copy number profiling, and functional assays. Analysis of these large, diverse data sets holds the promise of a more comprehensive understanding of the genome and its relation to human disease. Experienced and knowledgeable human review is an essential component of this process, complementing computational approaches. This calls for efficient and intuitive visualization tools able to scale to very large data sets and to flexibly integrate multiple data types, including clinical data. However, the sheer volume and scope of data pose a significant challenge to the development of such tools.

Integrative Genomics Viewer

Small-molecule H-bond donors in asymmetric catalysis.

Hydrogen bonding is responsible for the structure of much of the world around us. The unusual and complex properties of bulk water, the ability of proteins to fold into stable three-dimensional structures, the fidelity of DNA base pairing, and the binding of ligands to receptors are among the manifestations of this ubiquitous noncovalent interaction. In addition to its primacy as a structural determinant, hydrogen bonding plays a crucial functional role in catalysis. Hydrogen bonding to an electrophile serves to decrease the electron density of this species, activating it toward nucleophilic attack. This principle is employed frequently by Nature's catalysts, enzymes, for the acceleration of a wide range of chemical processes. Recently, organic chemists have begun to appreciate the tremendous potential offered by hydrogen bonding as a mechanism for electrophile activation in small-molecule, synthetic catalyst systems. In particular, chiral hydrogen-bond donors have emerged as a broadly applicable class of catalysts for enantioselective synthesis. This review documents these advances, emphasizing the structural and mechanistic features that contribute to high enantioselectivity in hydrogen-bond-mediated catalytic processes.

/pdf/asymmetric-catalysis-by-chiral-hydrogen-bond-donors-c4px56xxy0.pdf

Asymmetric catalysis by chiral hydrogen-bond donors.

Starting from the early 1990’s, the chemistry of polyvalent iodine organic compounds has experienced an explosive development. This surging interest in iodine compounds is mainly due to the very useful oxidizing properties of polyvalent organic iodine reagents, combined with their benign environmental character and commercial availability. Iodine(III) and iodine(V) derivatives are now routinely used in organic synthesis as reagents for various selective oxidative transformations of complex organic molecules. Several areas of hypervalent organoiodine chemistry have recently attracted especially active interest and research activity. These areas, in particular, include the synthetic applications of 2-iodoxybenzoic acid (IBX) and similar oxidizing reagents based on the iodine(V) derivatives, the development and synthetic use of polymer-supported and recyclable polyvalent iodine reagents, the catalytic applications of organoiodine compounds, and structural studies of complexes and supramolecular assemblies of polyvalent iodine compounds.

The chemistry of polyvalent iodine has previously been covered in four books1–4 and several comprehensive review papers.5–17 Numerous reviews on specific classes of polyvalent iodine compounds and their synthetic applications have recently been published.18–61 Most notable are the specialized reviews on [hydroxy(tosyloxy)iodo]benzene,41 the chemistry and synthetic applications of iodonium salts,29,36,38,42,43,46,47,54,55 the chemistry of iodonium ylides,56–58 the chemistry of iminoiodanes,28 hypervalent iodine fluorides,27 electrophilic perfluoroalkylations,44 perfluoroorgano hypervalent iodine compounds,61 the chemistry of benziodoxoles,24,45 polymer-supported hypervalent iodine reagents,30 hypervalent iodine-mediated ring contraction reactions,21 application of hypervalent iodine in the synthesis of heterocycles,25,40 application of hypervalent iodine in the oxidation of phenolic compounds,32,34,50–53,60 oxidation of carbonyl compounds with organohypervalent iodine reagents,37 application of hypervalent iodine in (hetero)biaryl coupling reactions,31 phosphorolytic reactivity of o-iodosylcarboxylates,33 coordination of hypervalent iodine,19 transition metal catalyzed reactions of hypervalent iodine compounds,18 radical reactions of hypervalent iodine,35,39 stereoselective reactions of hypervalent iodine electrophiles,48 catalytic applications of organoiodine compounds,20,49 and synthetic applications of pentavalent iodine reagents.22,23,26,59

The main purpose of the present review is to summarize the data that appeared in the literature following publication of our previous reviews in 1996 and 2002. In addition, a brief introductory discussion of the most important earlier works is provided in each section. The review is organized according to the classes of organic polyvalent iodine compounds with emphasis on their synthetic application. Literature coverage is through July 2008.

Chemistry of Polyvalent Iodine

Total synthesis of batzelladine K (1), a marine guanidine alkaloid, was achieved based upon successive 1,3-dipolar cycloaddition reaction of cyclic nitrone. The relative and absolute stereochemistry of 1 was established by spectral comparison of the natural and synthetic products and the trans-isomer, which was also synthesized.

Synthesis of (+)-batzelladine K

Oroidin derived, pyrrole imidazole marine alkaloids (PIAs) are attractive targets for synthetic organic chemists because of their structural complexity and diversity, as well as their interesting biological activities. A number of efforts have been carried out to develop strategies for the synthesis of these natural products. Members of PIAs (eg., 2-7), which contain tetracyclic ring systems possessing characteristic cyclic guanidine or urea moieties, show significant biological activities including anticancer activity and agonistic activity against the adrenoceptor. In this review, investigations of the total synthesis of the representative tetracyclic PIAs, dibromophakellin (2) and dibromophakellstatin (3), are described.

https://journals.sagepub.com/doi/pdf/10.1177/1934578X1300800722

Synthetic approaches to tetracyclic pyrrole imidazole marine alkaloids.

Total synthesis of (+)-cylindradine A

Saxitoxin (STX), a neurotoxin isolated from Alaskan butter clam, Saxidomus giganteus, inhibits voltage-gated sodium channels by binding to the pore-forming p-loop region. Here we describe stereospecific syntheses of STX and its natural derivatives, (+)-decarbamoylsaxitoxin (dcSTX) and (+)-gonyautoxin3 (GTX3).

Kazuo Nagasawa

Papers

Synthesis of (+)-batzelladine K

Synthetic approaches to tetracyclic pyrrole imidazole marine alkaloids.

Total synthesis of (+)-cylindradine A

Synthesis of saxitoxins

Analysis of the unbinding force between telomestatin derivatives and human telomeric G-quadruplex by atomic force microscopy