9-Fluorenylmethoxycarbonyl (Fmoc) amino acids were first used for solid phase peptide synthesis a little more than a decade ago. Since that time, Fmoc solid phase peptide synthesis methodology has been greatly enhanced by the introduction of a variety of solid supports, linkages, and side chain protecting groups, as well as by increased understanding of solvation conditions. These advances have led to many impressive syntheses, such as those of biologically active and isotopically labeled peptides and small proteins. The great variety of conditions under which Fmoc solid phase peptide synthesis may be carried out represents a truly "orthogonal" scheme, and thus offers many unique opportunities for bioorganic chemistry.

Solid phase peptide synthesis utilizing 9‐fluorenylmethoxycarbonyl amino acids

23 Stereocontrol of Lactide ROP 6164 231 Isotactic Polylactides 6164 232 Syndiotactic Polylactides 6166 233 Heterotactic Polylactides 6166 3 Anionic Polymerization 6166 4 Nucleophilic Polymerization 6168 41 Mechanistic Considerations 6168 42 Catalysts 6169 421 Enzymes 6169 422 Organocatalysts 6169 43 Stereocontrol of Lactide ROP 6170 44 Depolymerization 6170 5 Cationic Polymerization 6170 6 Conclusion and Perspectives 6171 7 Acknowledgments 6173 8 References and Notes 6173

Controlled ring-opening polymerization of lactide and glycolide.

Over the past decade, the most significant, conceptual advances in the field of fluorination were enabled most prominently by organo- and transition-metal catalysis. The most challenging transformation remains the formation of the parent C-F bond, primarily as a consequence of the high hydration energy of fluoride, strong metal-fluorine bonds, and highly polarized bonds to fluorine. Most fluorination reactions still lack generality, predictability, and cost-efficiency. Despite all current limitations, modern fluorination methods have made fluorinated molecules more readily available than ever before and have begun to have an impact on research areas that do not require large amounts of material, such as drug discovery and positron emission tomography. This Review gives a brief summary of conventional fluorination reactions, including those reactions that introduce fluorinated functional groups, and focuses on modern developments in the field.

/pdf/introduction-of-fluorine-and-fluorine-containing-functional-1i8kwiad20.pdf

Introduction of Fluorine and Fluorine-Containing Functional Groups

https://pharmrev.aspetjournals.org/content/pharmrev/46/2/205.full.pdf

International Union of Pharmacology classification of prostanoid receptors: properties, distribution, and structure of the receptors and their subtypes.

The substituted indole nucleus [indole is the acronym from indigo (the natural dye) and oleum (used for the isolation)] is a structural component of a vast number of biologically active natural and unnatural compounds. The synthesis and functionalization of indoles has been the object of research for over 100 years, and a variety of well-established classical methods are now available, to name a few of them, the Fisher indole synthesis, the Gassman synthesis of indoles from N-halo-anilines, the Madelung cyclization of N-acyl-o-toluidines, the Bischler indole synthesis, the Batcho-Leimgruber synthesis of indoles from o-nitrotoluenes and dimethylformamide acetals, and the reductive cyclization of o-nitrobenzyl ketones.1 In the last 40 years or so, however, palladiumcatalyzed reactions, generally tolerant of a wide range of functionalities and therefore applicable to complex molecules, have achieved an important place in the arsenal of the practicing organic chemist. Since the invention of an industrial process for the palladium-catalyzed production of acetaldehyde from ethylene in the presence of PdCl2 and CuCl2, an everincreasing number of organic transformations have been based on palladium catalysis. Almost every area of the organic synthesis has been deeply influenced by the profound potential of this versatile transition metal, modifying the way organic chemists design and realize synthetic processes.2,3 Because of its catalytic nature, palladium-catalyzed synthesis can provide access to fine chemicals, agrochemical and pharmaceutical intermediates, and active ingredients in fewer steps and with less waste than classical † In memory of Prof. Bianca Rosa Pietroni, a colleague and very close friend. * To whom correspondence should be addressed. Phone: + 39 (06) 4991-2785. Fax: + 30 (06) 4991-2780. E-mail: sandro.cacchi@ uniroma1.it. 2873 Chem. Rev. 2005, 105, 2873−2920

Synthesis and functionalization of indoles through palladium-catalyzed reactions

The synthesis of 4-dialkylaminopyridines can be accomplished in two steps starting from pyridine. Compared to pyridine, these derivatives are approximately 104 times more active when used as acylation catalysts. Dialkylaminopyridines are being used with ever-increasing frequency for acylation reactions which proceed either incompletely or not at all in pyridine. This article reviews the various possible applications of 4-dialkylaminopyridines in terpene, steroid, carbohydrate and nucleoside chemistry as well as in the transformation of amino acids into α-acyl aminoketones and polymerization of isocyanates. In addition, N-substituted 4-dialkylaminopyridinium salts can be used for the transfer of sensitive groups to nucleophiles in aqueous medium. The exceptional catalytic effect of these derivatives, even in non-polar solvents, is due, in part, to the formation of high concentrations of N-acylpyridinium salts which are present in solution as loosely-bound, highly reactive ion pairs.

4-Dialkylaminopyridines as Highly Active Acylation Catalysts. [New synthetic method (25)]

The novel Lewis acids (CH3)3SiOSO2CF3 (3), (CH3)5SiOSO2C4F9 (6), and (CH3)3SiClO4 (4) are highly selective and efficient Friedel-Crafts catalysts for nucleoside formation form silylated heterocycles and peracylated sugars as well as for rearrangements of persilylated protected nucleosides. With basic silylated heterocycles these new catalysts give much higher yields of the natural N-1-nucleosides than with SnCl4.

Nucleoside syntheses, XXII1) Nucleoside synthesis with trimethylsilyl triflate and perchlorate as catalysts

4‐Dialkylaminopyridine als hochwirksame Acylierungskatalysatoren

During the silyl-Hilbert-Johnson nucleoside synthesis with Friedel-Crafts catalysts three processes occur simultanously: 

A)
The formation of the electrophilic sugar cation.

B)
The σ-complex formation between th silylated base and the Friedel-Crafts catalyst and finally.

C)
The reaction of the electrophilic sugar cation with the silylated base to the nucleoside. Mode and rate of σ-complex formation between the silylated base and the Friedel-Crafts catalysts were monitored by 13C-NMR. The probable mechanism of nucleoside synthesis and the factors which influence course and yield of nucleoside synthesis are discussed.





Nucleosid-Synthesen, XXIII1) Uber den Mechanismus der Nucleosid-Synthese



In der Silyl-Hilbert-Johnson-Reaktion geschehen drei Prozesse gleichzeitig: 

A)
Die Bildung des elektrophilen Zucker-Kations.

B)
Die σ-Komplex-Bildung zwischen der silylierten Base und dem Friedel-Crafts-Katalysator.

C)
Die Reaktion des elektrophilen Zucker-Kations mit der silylierten Base zum Nucleosid. Art und Geschwindigkeit der σ-Komplex-Bildung zwischen der Silylierten Base und den Friedel-Crafts-Katalysatoren wurden mit Hilfe der 13C-NMR verfolgt. Der wahrscheinliche Mechanismus der Nucleosid-Synthese und die Faktoren, die Verlauf und Ausbeute der Nucleosid-Synthese beeinflussen, werden diskutiert.

Nucleoside Syntheses, XXIII1) On the Mechanism of Nucleoside Synthesis

The several steps of the Friedel-Crafts catalyzed silyl-Hilbert-Johnson nucleoside synthesis - silylation of the heterocyclic base, silylation of the perfluorosulfonic acids or its salts (if SnCl4 is not used as catalyst) and finally the nucleoside synthesis itself - can be combined to a simple one-step/one-pot reaction which generally affords nucleosides in high yields.

Helmut Vorbrüggen

Papers

4-Dialkylaminopyridines as Highly Active Acylation Catalysts. [New synthetic method (25)]

Nucleoside syntheses, XXII1) Nucleoside synthesis with trimethylsilyl triflate and perchlorate as catalysts

4‐Dialkylaminopyridine als hochwirksame Acylierungskatalysatoren

Nucleoside Syntheses, XXIII1) On the Mechanism of Nucleoside Synthesis

Nucleoside syntheses, XXV1) A new simplified nucleoside synthesis