Indoles, both naturally occurring and synthetic, exhibit wide-ranging biological activity. Unusual and complex molecular architectures occur among their natural derivatives. As a result, this important ring system continues to attract attention from the international chemical community, and new methodologies for the construction of this ever relevant heteroaromatic ring continue to be developed. Unfortunately, many methods frequently start from ortho-substituted anilines, thereby greatly restricting the availability of starting materials. A more general approach would start from a mono-functionalized arene such as an aniline or halobenzene, followed by cyclization with C–C or C–N bond formation to an unactivated C–H bond. Such methods are the subject of this perspective.

http://www.chtf.stuba.sk/~szolcsanyi/education/files/Chemia%20heterocyklickych%20zlucenin/Prednaska%202/Doplnkove%20studijne%20materialy/Indole/Indole%20synthesis%20%96%20something%20old,%20something%20new.pdf

Indole synthesis – something old, something new

A comparative study on the catalytic activity of a series of [IrCl 2 Cp*(NHC)] complexes in several C-O and C-N coupling processes implying hydrogen-borrowing mechanisms has been performed. The compound [IrCl 2 Cp*(I nBu )] (Cp* = pentamethyl cyclopentadiene; I nBU =1,3-di-n-butylimidazolylidene) showed to be highly effective in the cross-coupling reactions of amines and alcohols, providing high yields in the production of unsymmetrical ethers and N-alkylated amines. A remarkable feature is that the processes were carried out in the absence of base, phosphine, or any other external additive. A comparative study with other known catalysts, such as Shvo's catalyst, is also reported.

http://repositori.uji.es/xmlui/bitstream/handle/10234/22414/32155.pdf;sequence=1

[IrCl2Cp*(NHC)] Complexes as Highly Versatile Efficient Catalysts for the Cross-Coupling of Alcohols and Amines

Carbohydrates, which are ubiquitously distributed throughout the three domains of life, play significant roles in a variety of vital biological processes. Access to unique and homogeneous carbohydrate materials is important to understand their physical properties, biological functions, and disease-related features. It is difficult to isolate carbohydrates in acceptable purity and amounts from natural sources. Therefore, complex saccharides with well-defined structures are often most conviently accessed through chemical syntheses. Two major hurdles, regioselective protection and stereoselective glycosylation, are faced by carbohydrate chemists in synthesizing these highly complicated molecules. Over the past few years, there has been a radical change in tackling these problems and speeding up the synthesis of oligosaccharides. This is largely due to the development of one–pot protection, one–pot glycosylation, and one–pot protection–glycosylation protocols and streamlined approaches to orthogonally protect...

"One-Pot" Protection, Glycosylation, and Protection-Glycosylation Strategies of Carbohydrates.

This Perspective highlights the recent developments in the reduction of unsaturated substrates catalysed by main group element compounds. Various activation modes are discussed and comparison with relevant examples from transition metal systems is made when possible. Main group element catalysis offers significant advantages through its lower cost and more benign environmental impact and has now reached the point where it can successfully compete with the more common catalysis based on precious transition metals.

Main group catalysed reduction of unsaturated bonds.

Brevetoxin B emerged from the sea and into the laboratories of Nakanishi and Clardy who, in 1981, reported its magnificent and unprecedented structure. With its ladder-like fused polyether molecular architecture, potent toxicity, and fascinating voltage-sensitive sodium channel-based mechanism of action, it immediately captured the imagination of chemists around the world. Their synthetic escapades resulted in numerous new synthetic methods and strategies for the construction of cyclic ethers, and culminated in several impressive total syntheses of this imposing molecule and some of its equally challenging siblings that followed. Indeed, many more brevetoxin-type marine polyethers have been reported since 1981 with maitotoxin being not only the most complex and most toxic of the class, but also the largest non-polymeric natural product known to date. In this article, we begin with a brief history of these biotoxins and the phenomena that led to their isolation and highlight their biological properties and mechanism of action. We then review the chemical synthesis endeavors so far published in this long running saga, placing particular emphasis on the new synthetic methods and technologies discovered, developed and applied to their total syntheses over the last few decades. Finally, we conclude with a discussion of the, as yet unfinished, story of maitotoxin, and project into the future of this fascinating area of research.

/pdf/the-continuing-saga-of-the-marine-polyether-biotoxins-1pue42n37b.pdf

The Continuing Saga of the Marine Polyether Biotoxins

General ether synthesis under mild acid-free conditions. Trimethylsilyl iodide catalyzed reductive coupling of carbonyl compounds with trialkylsilanes to symmetrical ethers and reductive condensation with alkoxysilanes to unsymmetrical ethers

Kirtivan D. Kotian

Papers

General ether synthesis under mild acid-free conditions. Trimethylsilyl iodide catalyzed reductive coupling of carbonyl compounds with trialkylsilanes to symmetrical ethers and reductive condensation with alkoxysilanes to unsymmetrical ethers

Synthesis of indoles from N-(trifluoroacetyl)-2-anilino acetals

N-carboethoxypiperidine, a Convenient Reagent for the Preparation of Symmetrical Ketones from Organolithiums

Regiochemistry, stereochemistry, and mechanism of addition of trifluoroacetic acid to (Z)-cyclooctene

Stereochemistry and Mechanism of π-Assisted Solvolysis of endo-Bicyclo[3.3.1]non-6-ene-3-methyl Tosylate