Fishing for complements! There is an alternative to the useful Fischer indole synthesis. The new method utilizes the same retrosynthetic disconnection but is based on a RhIII‐catalyzed directed CH ...activation step and a successive coupling with alkynes.
N-heterocyclic carbene (NHC)-metal complexes have become known as efficient catalysts for numerous transition metal catalyzed processes. An important application of many NHC-metal complexes is in the ...field of asymmetric catalysis, and this is achieved through the introduction of chiral information on the NHC ligands. Among the asymmetric transformations catalyzed by NHC-metal complexes is asymmetric hydrogenation, which is an attractive process for the synthesis of optically active compounds due to its high atom economy. However, to date, few chiral NHC-metal catalysts have been reported to be highly stereoselective for asymmetric hydrogenation. Over the past few years our group has made some significant breakthroughs within the field of asymmetric hydrogenation using chiral NHC catalysts. We have reported the NHC-Ru catalyzed asymmetric hydrogenation of a wide range of heterocyclic compounds with high regio- and enantioselectivity. The field of chiral NHC-metal complex catalyzed asymmetric hydrogenation is yet to be reviewed; this Perspective aims to provide a concise overview of NHC-metal catalyzed asymmetric hydrogenation to push the further development of this area of chemistry.
Cu-Catalyzed Direct C6-Arylation of Indoles Yang, Youqing; Li, Ruirui; Zhao, Yue ...
Journal of the American Chemical Society,
07/2016, Letnik:
138, Številka:
28
Journal Article
Recenzirano
The first example of direct and site-selective arylation of indoles at the C6 position has been reported. The key to this high regioselectivity is the appropriate choice of the N–P(O) t Bu2 ...directing group and the use of diaryliodonium triflate salts as the coupling partners in the presence of catalytic CuO. The protocol is distinguished by mild reaction system that avoids ligand and additives, exhibiting wide scope of indole and arene coupling components without compromising its efficiency and scalability, thus representing a significant advancement in the implementation of regioselective direct arylation of indoles.
Herein, we report three-component vicinal-diarylation of non-conjugated alkenes initiated by transmetalation of arylboronic acids, which provides complementary access to β,γ-diaryl carbonyl ...compounds. We have also screened a large number of chiral ligands for developing an enantioselective version of this reaction and obtained the preliminary results (up to 79 : 21 e.r.). Notably, the methodology developed herein represents the first three component
-vicinal-dicarbofunctionalization of non-conjugated alkenes involving palladium catalysis.
The biheteroaryl structural motif is prevalent in polymers, advanced materials, liquid crystals, ligands, molecules of medicinal interest, and natural products. Many types of synthetic ...transformations have been known for the construction of heteroaryl–heteroaryl linkages. Coupling reactions provide one of the most efficient ways to achieve these biheterocyclic structures. In this review, four types of coupling reactions are discussed: 1) transition‐metal‐catalyzed coupling reactions of heteroaryl halides or surrogates with heteroarylmetals; 2) direct inter‐ and intramolecular heteroarylations of C sp 2H bonds of heteroarenes with heteroaryl halides or pseudohalides; 3) oxidative CH/CH homo‐ and cross‐couplings of two unpreactivated heteroarenes; and 4) transition‐metal‐catalyzed decarboxylative cross‐coupling reactions between haloheteroarenes or heteroarenes and heteroarenecarboxylic acids. The general purpose of this review is to give an exhaustive and clear picture in heteroaryl–heteroaryl bond formation as well as its application in the synthesis of natural products, pharmaceuticals, catalyst ligands, and materials.
Opposites attract: The biheteroaryl structural motif is prevalent in polymers, advanced materials, molecules of medicinal interest, and natural products. In this article, four types of coupling reactions are reviewed. The general purpose of this review is to give a clear picture in heteroaryl–heteroaryl bond formation as well as its application in the synthesis of natural products, pharmaceuticals, catalyst ligands, and materials.
Transition metal-catalyzed reactions of silacyclobutanes with a variety of π units have attracted much attention and become one of the most straightforward and efficient approaches to rapidly access ...structurally diverse organosilicon compounds. However, the reaction of silacyclobutanes with alkynes still suffers from some limitations: (1) internal alkynes remain challenging substrates; (2) expensive Pd- or Rh-based catalysts have been employed in all existing systems; (3) controlling chemodivergence has not yet been realized. Herein we realize Ni-catalyzed chemodivergent reactions of silacyclobutanes with alkynes. In comparison with the previous Pd or Rh catalytic systems, our Ni-catalytic system features: 1) complementary substrate scope; 2) ligand-controlled chemodivergence; 3) low cost. The ligand precisely dictates the pathway selectivity, leading to the divergent formation of (benzo)silacyclohexenes and allyl vinylsilanes. Moreover, we demonstrate that employment of a chiral phosphine ligand is capable of forming silicon-stereogenic allyl vinylsilanes in high yields and enantioselectivities. In addition, DFT calculation is performed to elucidate the origin of the switchable selectivities, which is mainly attributed to different ligand steric effects.
A RhIII‐catalyzed C–H activation/cyclative capture approach, involving a nucleophilic addition of C(sp3)–Rh species to polarized double bonds is reported. This constitutes the first intermolecular ...catalytic method to directly access 1‐aminoindolines with a broad substituent scope under mild conditions.
Buckle up! The nucleophilic addition of C(sp3)–Rh species to polarized double bonds is the key step in a RhIII‐catalyzed C–H activation/cyclative capture reaction. This constitutes the first intermolecular catalytic method to directly access the 1‐aminoindoline core with a broad substituent scope under mild conditions (Boc=tert‐butoxycarbonyl, DG=directing group).
Herein, a rhodium(III)-catalyzed oxidative C–H activation of simple arylphosphonates and phosphonamides with subsequent coupling with alkenes (olefination), internal alkynes (hydroarylation and ...oxidative cyclization), or simple arenes to give access to diverse P-containing functional frameworks is reported.
The development of a straightforward strategy to obtain enantioenriched silicon‐stereogenic benzosiloles remains a challenging yet appealing synthesis venture due to their potential future ...application in chiral electronic and optoelectronic devices. In this context, all of the existing methods rely on Rh‐catalyzed systems and are somewhat limited in scope. Herein, we disclose the first Ni0‐catalyzed ring expansion process that enables the preparation of benzosiloles possessing tetraorganosilicon stereocenters in excellent yields and enantioselectivities. The presented catalysis strategy is further applied to the asymmetric synthesis of silicon‐stereogenic bis‐silicon‐bridged π‐extended systems. Preliminary studies reveal that such compounds exhibit fluorescence emission, Cotton effects and circularly polarized luminescence (CPL) activity.
We disclosed a state‐of‐the‐art strategy for the asymmetric synthesis of enantioenriched silicon‐stereogenic benzosiloles in excellent yields and enantioselectivities enabled by a Ni0/chiral PR3‐catalyst system. Moreover, preliminary studies on the chiroptical properties of silicon‐stereogenic bis‐silicon‐bridged π‐extended systems, which were synthesized by the presented catalysis strategy, are also described.
1,2-Bis-silyl alkenes have exciting synthetic potential for programmable sequential synthesis via manipulation of the two vicinal silyl groups. Transition metal-catalyzed bis-silylation of alkynes ...with disilanes is the most straightforward strategy to access such useful building blocks. However, this process has some limitations: (1) symmetric disilanes are frequently employed in most of the reactions to assemble two identical silyl groups, which makes chemoselective differentiation for stepwise downstream transformations difficult; (2) the main catalysts are low-valent platinum group transition metal complexes, which are expensive; and (3) internal alkynes remain challenging substrates with low inherent reactivity. Thus, the development of abundant metal-catalyzed bis-silylation of internal alkynes with unsymmetrical disilanes is of significance. Herein, we solve most of the aforementioned limitations in bis-silylation of unsaturated bonds by developing a strongly coordinating disilane reagent and a Ni(0) catalytic system. Importantly, we sufficiently realize the stepwise recognition of the two silyl groups, making this synthetic protocol of wide potential utility.
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