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The copper-catalyzed enantioselective C-H arylation between 2-arylindoles and hypervalent iodine reagents has been successfully developed, which provides a convenient and economical route to the highly atroposelective synthesis of axially chiral indole de

An efficient Cu(I)/DMAP/air system for the one-pot synthesis of 4-oxo-4H-cinnolin-2-ium-1-ides, which are often difficult to prepare by traditional routes from substituted 2-alkynylanilines and nitrosoarenes, was developed. These 4-oxo-4H-cinnolin-2-ium-1-ides have practical applications as mechanoluminescent materials. Preliminary mechanistic experiments were performed, and a plausible mechanism for this tandem process is proposed. The use of an inexpensive copper catalyst and molecular oxygen as the oxygen source and the oxidant make this an attractive green protocol with potential synthetic applications.

We describe the divergent construction of two nitrogen-containing polycyclic systems by gold-catalyzed cycloisomerizations. The gold-catalyzed cascade hydroamination and 7-endo-dig-selective cycloisomerization of nitrogen-tethered 1,8-diynes yielded indol

N-Alkyl-N-(2-(1-arylvinyl)aryl)cinnamamides are converted into natural product inspired scaffolds via iridium photocatalyzed intramolecular [2+2] photocycloaddition. The protocol has a broad substrate scope, whilst operating under mild reaction conditions. Tethering four components forming a trisubstituted cyclobutane core builds rapidly high molecular complexity. Our approach allows the design and synthesis of a variety of tetrahydrocyclobuta[c]quinolin-3(1H)-ones, in yields ranging between 20–99 %, and with excellent regio- and diastereoselectivity. Moreover, it was demonstrated that the intramolecular [2+2]-cycloaddition of 1,7-enynes—after fragmentation of the cyclobutane ring—leads to enyne-metathesis-like products.

Domino processes initiated by intramolecular nucleopalladation of alkynes have been developed into powerful synthetic tools for the synthesis of functionalized heterocycles. However, a catalytic enantioselective version of this class of reactions remains

A Pd(ii)/Cu(ii) catalysed domino synthesis of tricyanovinylindoles has been achieved using DMSO as a one-carbon synthon. The reaction proceedsviathe construction of 2-aryl-3-formyl indole followed by sequential addition of malononitrile and a CN resulting

We herein described a nickel-catalyzed cyclization ofN-(o-ethynylaryl)acrylamides for the selective synthesis of dihydrocyclobuta[c]quinolin-3-ones and benzo[b]azocin-2-ones. The two varied products could be easily obtained by tuning the reaction temperature. This reaction features easy temperature-control, high efficiency, and gram-scale synthesis.

A Cu(I)-mediated cascade cyclization/annulation of unprotectedo-alkynylanilines with maleimides in one pot is developed. The protocol offers sequential formation of one C-N and two C-C bonds to deliver fused benzo[a]carbazoles having free NH skeletons. The annulated products display fluorescence emission in the range of 485-502 nm with a large Stokes shift and fluorescence lifetime of ～17 ns. The annulated3aadisplays AEE behavior in the ethanol/hexane system and possesses marigold-flower-like morphology at the aggregated state. Cell viability assays enumerate biocompatible AEEgens, while their high intracellular fluorescence depicts cell imaging applicability.

We demonstrated a highly competitive and selective C-C and N-C cross-coupled 7-, 6- and 5-annulation utilizing 2-ethynylanilides to afford functionalized 1H-benzo[b]azepin-2(5H)-ones, 2-quinolinones, and 3-acylindoles in high yield. ZnCl2 was f

Indole and phthalide are privileged heterocyclic scaffolds in numerous natural products and bioactive molecules. The synthesis and biological evaluation of the compounds combining these two scaffolds have rarely been reported. Herein, we repot the first palladium-catalyzed ligand-free double cyclization reactions that enable efficient synthesis of 3-(1′-indolyl)-phthalides (42 examples, up to 96% yield) under mild conditions. Notably, only 1.0 mol % of catalyst loading is used, suggesting high efficiency. Late-stage elaborations give highly functionalized analogues.

We describe here a Cu-catalyzed and 4-OH-TEMPO-mediated sequential dehydrogenation/aza-Michael addition/annulation cascade reaction for the construction of N-alkyl 2-arylindoles from facilely available saturated ketones and 2-arylethynylanilines. This rea

Herein, we describe a new protocol for photoinduced radical [2+2+1] carbocyclization reactions of 1,7-enynes with bromofluoroacetate. These reactions, which proceed via a cascade involving fluoroalkylation, 6-exo-dig and 5-endo-trig cyclizations, H-transf

Benzylation of alcohols with benzyl (Z)-2,2,2-trifluoro-N-(2-alkynylphenyl)acetimidates 5a-f in the presence of a cationic gold(I) catalyst was investigated. Reagent 5f was the most effective, affording benzyl ethers in good yields. Our results indicate that these gold(I)-activated imidates are effective leaving groups.

An efficient and practical approach for the synthesis of 3-indolyl-C-Δ1,2-glycosides through a palladium-catalyzed annulation/C-glycosylation sequence of o-alkynylanilines with 1-iodoglycals has been developed. This methodology has a wide scope of substra

A highly efficient Pd-catalyzed Sonogashira coupling of various aryl fluorides with terminal alkynes in the presence of LiHMDS was developed. Both unreactive electron-rich fluoroarenes and electron-poor fluoroarenes proceeded smoothly and afforded the cor

Efficient one-pot synthesis of N-imidoyl-(1H)-indoles has been described, which is achieved by the palladium-catalyzed oxidative insertion of 2-(phenylethynyl)aniline, arylboronic acid, and isonitrile. This method provides a new way to synthesize N-imidoy

An atom-economical method for synthesizing N-heterocyclic indoles from readily available o-alkynylphenyl isothiocyanates and propargylamine derivatives is reported. This method involves a copper-catalyzed cascade bicyclization process consisting of an int

An asymmetric cobalt-catalyzed hydroboration/cyclization of 1,7-enynes to synthesize chiral six-membered N-heterocyclic compounds was developed. A variety of aniline-tethered 1,7-enynes react with pinacolborane to afford the corresponding chiral boryl-fun

No Abstract. (Figure presented.).

Porous multipod Cu2O microcrystals were found to be an efficient, highly recyclable and eco-friendly catalyst for the cross-coupling reactions of aryl halides and terminal alkynes with high yields in aqueous media. Noteworthy, the Cu2O catalyst can be reused for several times without significant decrease in catalytic activity.

A simple, mild, efficient and chemoselective catalytic method for the straightforward synthesis of an interesting class of 2-aryl/alkyl-substituted-3-diaryl indolyl methanes in high yield is reported. This atom-efficient method proceeds via a gold-catalyzed one-pot sequential intramolecular hydroamination (C-N bond formation) of 2-alkynylanilines followed by a 1,6-conjugate addition to p-quinonemethides. The p-quinonemethides, which contain aldehyde functional groups, preferentially participate in 1,6-conjugate addition, while the aldehyde functional group remains unreactive.

An efficient synthesis of N-acetyl-2-substituted indole derivatives via direct intramolecular hydroamination of N-acetyl-2-alkynylaniline derivatives was developed. The reaction could be applied to a wide range of substrates employing only 1–2 mol% of PtCl4 as the catalyst to furnish the desired indole products in moderate to excellent yields. The current protocol is efficient, reliable and scalable, and could serve as an important tool for convenient and rapid access to this important class of N-heterocyclic skeleton from readily available substrates.

We describe an efficient catalyst- and metal-free aminoboration of alkynes to 3-borylated indoles using one of the least expensive boron sources, BCl3. The major dichloro(indolyl)borane products can be used for the in situ construction of usefu

A novel copper-catalyzed cascade radical sulfonylation of N-propargyl-substituted indoles with concomitant 1,2-aryl migration was described. The protocol, which has good functional-group tolerance, provides practical, versatile and atom-economical method of accessing a new class of fascinating 2-sulfonated pyrrolo[1,2-α]indole derivatives in moderate to good yields through the formation of the new C?S, C?C and C=O bonds in a one-step. (Figure presented.).

A new transition-metal-free version for the synthesis of π-conjugated quinazoline-substituted ethene derivatives from readily available starting materials has been developed. Quinazoline-substituted ethenes were obtained in moderate to high yields with completely Z-selectivity, and the resulting quinazoline-substituted ethenes show typical aggregation-induced emission (AIE) properties.

A novel cascade annulation of 1,7-diynes with water has been developed for the synthesis of furo[3,4-c]quinolin-4(5H)-one skeletons with high atom- and step-economy. The transformation was enabled by a palladium catalyst in the presence of copper salt as

The reaction of 2-alkynyl anilines with catalytic amounts of B(C6F5)3 (5 mol%) resulted in the formation of 2-substituted indoles according to an intramolecular hydroamination in good to excellent yields. Reaction intermediates as well as products were characterized by NMR spectroscopy and by X-ray crystallography. The domino hydroamination/hydrogenation sequence allowed the efficient synthesis of tetrahydroquinoline 8 in good yield.

A Pt-catalyzed, highly regioselective reaction between N-allenamides and imino-alkynes leading to pyrrolo[1,2-a]indoles is described. This represents the first example of [3+2]-annulation of Pt-bound azomethine ylides with the distal C=C bond of N-allenam

Nickel(II) can be used to catalyze the hetero [2+2+1] cycloaddition of 2-alkynylaryl isothiocyanates and isonitriles in 2-methyltetrahydrofuran (2-MeTHF) to give a wide array of thieno[2,3-b]indoles in excellent yields. The reaction is featured by employi

A Br?nsted acid-catalyzed annulation strategy has been developed to construct indeno[1,2-c]quinolines. This tandem synthetic method proceeds through a sequential electrophilic addition followed by a Friedel–Crafts-type reaction. A variety of tetracyclic c

An efficient strategy for the easy access to carbonylated heteroaromatic compounds has been developed via a visible-light-promoted intramolecular decarboxylative cyclization reaction of o-alkynylated carboxylic acids. This method is characterized by its b

A set of reactions involving copper-catalyzed trifluoromethylazidation and then rearrangement of aniline-linked 1,7-enynes with the relatively poorly reactive Togni reagent I and TMSN3 was developed, and provided facile access to structurally d

An alternative entry to transformations of N-sulfonyl-4-(2-(ethynyl)aryl)-1,2,3-triazoles with various generated in situ or external nucleophiles by means of silver catalysis for producing diverse functionalized isoquinolines is described. Mechanistically

A base-promoted synthesis of quinoline-4(1H)-thiones has been accomplished from the in situ generated o-alkynylthiourea, obtained by reacting o-alkynylanilines with aroyl/acyl isothiocyanates. A 6-exo-dig S-cyclization of the in situ generated thiourea is

An efficient palladium-catalyzed dearomatizing [2+2+1] carbocyclization of 1,7-enynes with iodophenols has been developed. A type of tetracyclic scaffold was built in this reaction, exhibiting a broad substrate scope with moderate to excellent yields. More importantly, this method provides a potential strategy for the synthesis of tetracyclic skeleton natural products.

Liver X receptor (LXR) agonists are candidates for the treatment of atherosclerosis via induction of ABCA1 (ATP-binding cassette A1) gene expression, which contributes to reverse cholesterol transport (RCT) and to cholesterol efflux from the liver and intestine. However, LXR agonists also induce genes involved in lipogenesis, such as SREBP-1c (sterol regulatory binding element protein 1c) and FAS (fatty acid synthase), thereby causing an undesirable increase in plasma and hepatic triglyceride (TG) levels. Recent studies indicate that LXRα contributes to lipogenesis in liver, and selective LXRβ activation improves RCT in mice. Therefore, LXRβ-selective agonists are promising candidates to improve atherosclerosis without increasing plasma or hepatic TG levels. However, the ligand-binding domains in the two LXR isoforms α/β share high sequence identity, and few LXR ligands show subtype selectivity. In this study we identified a tetrachlorophthalimide analogue as an LXRβ-selective agonist. Structural development led to (E)-4,5,6,7-tetrachloro-2-(2-styrylphenyl)isoindoline-1,3-dione (24 a), which shows potent and selective LXRβ agonistic activity in reporter gene assays. In binding assays, compound 24 a bound to LXRβ preferentially over LXRα. It also induced the expression of ABCA1 mRNA but not SREBP-1c mRNA in cells. Compound 24 a appears to be a promising lead compound for therapeutic agents to treat atherosclerosis without the side effects induced by LXRα/β dual agonists.

We report a highly robust, general and stereoselective method for the synthesis of 3-(chloromethylene)oxindoles from alkyne-tethered carbamoyl chlorides using PdCl2(PhCN)2 as the catalyst. The transformation involves a stereo- and regioselective chloropalladation of an internal alkyne to generate a nucleophilic vinyl PdII species, which then undergoes an intramolecular cross-coupling with a carbamoyl chloride. The reaction proceeds under mild conditions, is insensitive to the presence of moisture and air, and is readily scalable. The products obtained from this reaction are formed with >95:5 Z:E selectivity in nearly all cases and can be used to access biologically relevant oxindole cores. Through combined experimental and computational studies, we provide insight into stereo- and regioselectivity of the chloropalladation step, as well as the mechanism for the C-C bond forming process. Calculations provide support for a mechanism involving oxidative addition into the carbamoyl chloride bond to generate a high valent PdIV species, which then undergoes facile C-C reductive elimination to form the final product. Overall, the transformation constitutes a formal PdII-catalyzed intramolecular alkyne chlorocarbamoylation reaction.

An efficient, environmentally friendly, and operationally simple procedure to 1,2-disubstituted indoles from 2-alkynylanilines and diaryliodonium salts has been developed. This reaction proceeds smoothly under metal-free conditions. The products obtained could be transferred into 3,3′-diindolylmethane with DMSO catalyzed by palladium. The isotopic label experiments indicated that the methylene group in 3,3′-diindolylmethane is derived from DMSO. The diverse indoles were obtained in up to 90% yield for 28 examples.

A visible light promoted and TBHP mediated oxidative reaction of N-2-alkynylphenyl α-amino carbonyl compounds to N-2-alkynylphenyl oxalic amides was developed. In the presence of CuBr and photocatalyst Ru(bpy)3Cl2·6H2O, the reaction proceeded smoothly to afford the corresponding oxalic amides under the irradiation of a 26 W compact fluorescence bulb at room temperature. Furthermore, N-2-alkynylphenyl oxalic amides could be subsequently transferred to 2-aryl indoles without an additional deacylation step through a favored 5-endo-dig N-cyclization process using AgNO3 as catalyst.

Inspired by the Hegedus aza-Wacker indole synthesis, we were intrigued with the fate of the aminopalladation intermediate if syn β-hydrogen is made inaccessible or unavailable. In contrast to our previously reported β-carbon elimination, cyclization of a

A simple and straightforward approach was developed to construct 5H-benzo[b]carbazole derivatives by iron catalysis in a cascade sequence. The notable features of this work include an atom-economical cascade sequence, unprecedented 1,4-sulfonyl migration,

A novel synthetic route to benzo[f]dihydroisoquinolone through a p-TsOH promoted cascade cyclization of easily accessible diyne-tethered ynamides in the presence of a Au(I)-catalyst is described. This reaction unveils a broad substrate scope, constructing a wide range of benzo[f]dihydroisoquinolones in good yields. The diyne-tethered ynamides are synthesized from inexpensive o-iodoaniline through Sonogashira couplings and the Cu-mediated C-N bond formation. The role of p-TsOH is examined, and the reaction pathway is also deduced. The benzo[f]isoquinoline scaffold is constructed from benzo[f]dihydroisoquinolones.

An effective metal-free C-H amination of N-Ts-2-alkenylanilines by using DDQ as an oxidant has been developed to afford a diverse range of substituted indoles. This protocol is operationally simple and robust, obviates the need of expensive transition-metal catalysts, and offers a broad substrate scope. A mechanism involving a radical cation generated by SET and a migratorial process via a phenonium ion intermediate is proposed.

Two diphosphane ligands - 2,5-bis(2-(diphenylphosphino)-5-R)phenyl)-1,3,4- oxadiazole (L1, R = H, L2, R = OMe) and their binuclear complexes, L1Cu and L2Cu, were prepared and characterized. The molecular structures of L1Cu and L2Cu, as perchlorate salts,

Highly efficient approaches to obtain structurally diverse fluorinated indole derivatives have been realized through the Ag-catalyzed one-pot cyclization/fluorination of 2-alkynylanilines in the presence of NFSI or Selectfluor. The Royal Society of Chemistry.

Palladium-catalyzed Heck alkynylation cross-coupling reactions between terminal alkynes and deactivated aryl chlorides and aryl bromides can be performed in the absence of copper cocatalyst with water as solvent at 130 °C under microwave irradiation. An oxime-derived chloro-bridged palladacycle is an efficient precatalyst for this transformation with 2- dicyclohexylphosphanyl-2',4',6'-triisopropylbiphenyl (XPhos as ancillary ligand, pyrrolidine as base, and SBDS as surfactant. All of the reactions can be performed under air and with reagent-grade chemicals under low loading conditions (0.1-1 mol-% Pd). Deactivated and hindered aryl bromides and chlorides are cross-coupled with terminal alkynes by using low catalyst loadings of an oxime palladacycle, pyrrolidine as base, sodium dodecylbenzenesulfonate (SBDS as surfactant, water as solvent, and microwave irradiation (40 W at 130 °C. Under these reaction conditions a wide array of tolane derivatives are prepared in moderate-to-good yields. Copyright

Although 4-hydroxyquinolin-2(1H)-one derivatives have attracted much attention due to their biological benefits, conventional reactions under harsh heat conditions must be employed to provide these key compounds. In the presence of a catalytic amount of s

Elevated by the support: 2-Alkynyl aniline cycloisomerization to indole is catalyzed by cationic Au NPs on a carbon support. Electroneutral and rich 2-aryl indoles are further converted into 3,3′-biindoles by oxidative homocoupling that is readily catalyzed by the Au NPs on carbon, and exclusively but also somewhat sluggishly by the carbon support. Copyright

Protonated 1,8-diazabicyclo[5,4,0]undec-7-ene as catalyst for cascade addition/cyclization of 2-alkynylaniline and carbon disulfide has been described. This process provides a convenient route for synthesis of a variety of benzo[d][1,3]thiazine-2(4H)-thio

A highly efficient method for the synthesis of fluorine-containing multisubstituted phenanthridines through Rh-catalyzed alkyne [2+2+2] cycloaddition reactions has been developed. This method exhibits excellent functional-group compatibility. When a bromodifluoromethyl group, rather than a trifluoromethyl group, was employed in the cycloaddition reaction, more-complicated polycyclic compounds were obtained through tandem Rh-catalyzed cycloaddition/C-H difluoromethylenation. This route provides convenient access to fluorine-containing polycyclic compounds. [2+2+2] Little boys: Fluorine-containing multisubstituted phenanthridines have been synthesized through Rh-catalyzed alkyne [2+2+2] cycloaddition reactions (see scheme; FG=functional group). Polycyclic compounds were also obtained through Rh-catalyzed C-H difluoromethylenation. Copyright