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Advances in transition metal (Pd, Ni, Fe)-catalyzed cross-coupling reactions using alkyl-organometallics as reaction partners.

Electrophilic Trifluoromethylation by Use of Hypervalent Iodine Reagents

The impact of the development of sulfur therapeutics is instrumental to the evolution of the pharmaceutical industry. Sulfur-derived functional groups can be found in a broad range of pharmaceuticals and natural products. For centuries, sulfur continues to maintain its status as the dominating heteroatom integrated into a set of 362 sulfur-containing FDA approved drugs (besides oxygen or nitrogen) through the present. Sulfonamides, thioethers, sulfones and Penicillin are the most common scaffolds in sulfur containing drugs, which are well studied both on synthesis and application during the past decades. In this review, these four moieties in pharmaceuticals and recent advances in the synthesis of the corresponding core scaffolds are presented.

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Sulfur Containing Scaffolds in Drugs: Synthesis and Application in Medicinal Chemistry

Allenes are highly valuable synthetic precursors in preparative organic chemistry because of their ability to undergo a variety of transformations. Among many different reaction modes, activation of the cumulated double bonds by treatment with a Brønsted or Lewis acid is particularly useful because it allows a nucleophilic attack, which leads to the formation of a new C-C or Cheteroatom bond in an interor intramolecular fashion. Because of their axial chirality, allenes can undergo this bond formation with chirality transfer, which renders the method attractive for stereoselective target-oriented synthesis. Because of their soft and carbophilic character, gold catalysts are particularly well suited for the selective activation of allenes in the presence of other reactive functionalities. Compared to intermolecular additions, gold-catalyzed cyclization reactions of allenes by intramolecular nucleophilic attack have received much more attention. Here, the gold catalyst can coordinate to either allenic double bond, and the regioselectivity of the subsequent nucleophilic attack depends on the structure of the substrate, in particular the length of the tether connecting allene and nucleophile (Scheme 1). Hence, four different endoor exo-cyclization products can be obtained, but the formation of fiveor sixmembered rings via σ-gold species A or D, i.e., by nucleophilic attack at a terminal allenic carbon atom, is favored in most cases, whereas products arising from nucleophilic attack at the central allenic carbon atom (via intermediates B and C) are rare. Normally, these cyclization products are chiral and can be accessed in a stereoselective manner either from chiral allenes by axis-to-center chirality transfer or from achiral allenes utilizing chiral gold catalysts. This account comprises gold-catalyzed cyclization reactions of allenes by attack of carbon or heteroatom nucleophiles. Intermolecular addition reactions to allenes, as well as gold-catalyzed transformation of nonallenic substrates in which an allene is generated in situ (e.g., by sigmatropic rearrangement) and converted without isolation, will not be covered.

Gold-catalyzed nucleophilic cyclization of functionalized allenes: a powerful access to carbo- and heterocycles.

Synthesis of Heterocycles via Palladium-Catalyzed Carbonylations

The introduction of sulfur atoms onto target molecules is an important area in organic synthesis, in particular in the synthesis of pharmaceutical compounds, and a wide variety of sulfuration agents have been developed for thionation reactions over the past few decades. In this Focus Review, we collect and summarize the C-S bond-formation reactions that have been used to construct C-S bonds in natural products and pharmaceutical compounds.

Transfer of sulfur: from simple to diverse.

Construction of sulfur-containing moieties in the total synthesis of natural products

Trifluoromethylation meets CH activation: after transition metal-catalyzed trifluoromethylation became more and more popular, trifluoromethylation via CH activation is now emerging as the latest attraction. Several pioneering examples and their mechanisms are discussed in this review.

Xuefeng Jiang

Papers

Sulfur Containing Scaffolds in Drugs: Synthesis and Application in Medicinal Chemistry

Transfer of sulfur: from simple to diverse.

Construction of sulfur-containing moieties in the total synthesis of natural products

Direct Trifluoromethylation of the CH Bond

Efficient access to 1,4-benzothiazine: palladium-catalyzed double C-S bond formation using Na2S2O3 as sulfurating reagent.