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The confinement of a catalytic site is an efficient strategy to control a reaction and modulate its selectivity. In the present work, a new class of structurally simple and easily accessible bulky tri‐(ortho‐biaryl)phosphine ligands were accessed, and their gold(I) complexes synthesized. Their X‐ray diffraction analysis and the comparative evaluation of their VBur% and G steric parameters against a series of gold complexes commonly employed in catalysis demonstrated their confined nature. Despite their notable steric congestion, these complexes exhibited remarkable catalytic activities and unusual selectivities, both in nature and level, that make them unique in the field of synthetic homogeneous gold catalysis. [ABSTRACT FROM AUTHOR]

The confinement of a catalytic site is an efficient strategy to control a reaction and modulate its selectivity. In the present work, a new class of structurally simple and easily accessible bulky tri‐(ortho‐biaryl)phosphine ligands were accessed, and their gold(I) complexes synthesized. Their X‐ray diffraction analysis and the comparative evaluation of their VBur% and G steric parameters against a series of gold complexes commonly employed in catalysis demonstrated their confined nature. Despite their notable steric congestion, these complexes exhibited remarkable catalytic activities and unusual selectivities, both in nature and level, that make them unique in the field of synthetic homogeneous gold catalysis. [ABSTRACT FROM AUTHOR]

A new procedure for the synthesis of allenamides and structurally related compounds is reported. Under gold catalysis, a series of ynamides possessing a benzyloxy group at the propargylic position were efficiently converted into the corresponding allenamides following a 1,5 hydride shift process. The scope of the reaction was shown to be extremely broad allowing the formation of γ-mono or γ-disubstituted allenes possessing various functional groups. Notably, and in contrast to previously reported methods, not only N-allenyl sulfonamido but also urea, phosphonamido and the rarely studied phthalimido, pyrrolo, indolo and carbazolo derivatives could be readily and efficiently accessed. [ABSTRACT FROM AUTHOR]

Denitrogenative 6-endo-dig azide–yne cyclization of α-propargyloxy-β-haloalkylazides was enabled by gold catalysis, thus providing 2H-1,3-oxazines. This rare cyclization mode in gold-catalyzed reactions of azide–yne substrates was demonstrated to be facilitated and controlled by electronic and resonance effects of the alkyne substituents. Molecular transformations of the as-prepared 2H-1,3-oxazines were also investigated. [ABSTRACT FROM AUTHOR]

Simply complex: The title reaction proceeds at a low loading of catalyst (1 mol %) and allows an efficient and stereoselective access to the hydroazulenic motif, which is found in numerous natural products having significant biological activities. Tf=trifluoromethanesulfonyl, XPhos=2‐dicyclohexylphosphino‐2′,4′,6′‐triisopropylbiphenyl. [ABSTRACT FROM AUTHOR]

Doppelter Ringschluss: Die Titelreaktion mit nur 1 Mol ‐ % Katalysator öffnet einen stereoselektiven Zugang zum Hydroazulen ‐ Motiv, das in zahlreichen biologisch aktiven Naturstoffen zu finden ist. Tf=Trifluormethansulfonyl, XPhos=2 ‐ Dicyclohexylphosphanyl ‐ 2′,4′,6′ ‐ triisopropylbiphenyl. [ABSTRACT FROM AUTHOR]

A series of allenyl ethers can be transformed into various fused or spiro tetrahydrofurans and tetrahydropyrans following a hydride shift/cyclization sequence. A divergence in product selectivity, which depends on the nature of the catalyst used (Au(I) complex or Brønsted add), was observed. [ABSTRACT FROM AUTHOR]

Abstract: A study concerning the gold(I)-catalyzed hydroarylation of N-propargyl-N′-arylhydrazinecarboxylic acid methyl esters is described. The use of the gold complex [XPhosAu(NCCH3)SbF6] as the catalyst in refluxing nitromethane allows the generally rapid and efficient synthesis of a range of functionalized 4-exo-methylene-1,2-dihydrocinnolines. [ABSTRACT FROM AUTHOR]

Gold(I)-catalyzed cyclization of pentenynyl ally! ethers allows the rapid construction of functionalized furans. The concerted oxy-Claisen-type mechanism induces a complete selectivity of the process and allows the easy formation of quaternary centers. [ABSTRACT FROM AUTHOR]

(3+2) cycloaddition reactions are undeniably one of the most robust and versatile synthetic tools in heterocyclic chemistry. The classically required 1,3‐dipoles are however limited to three‐atom sequences bearing stabilized formal charges in their Lewis structure. The scope of three‐atom groupings possible in (3+2) cycloadditions can be greatly expanded by taking of advantage neutral three‐atom components (TACs). These groupings result in zwitterionic (3+2) cycloadducts adaptable to multiple outcomes depending on structure and conditions. Herein, the intramolecular (3+2) cycloaddition reaction between alkynyl sulfides (neutral TAC) and alkynes to provide key thiophenium ylide intermediates is first reported. These reactive species provide access to highly substituted fused thiophenes following predictable chemical sequences. Structural features on the obtained thiophenes were highly configurable by judicious choice of both alkynyl sulfide substitution and reaction conditions. [ABSTRACT FROM AUTHOR]

(3+2) cycloaddition reactions are undeniably one of the most robust and versatile synthetic tools in heterocyclic chemistry. The classically required 1,3‐dipoles are however limited to three‐atom sequences bearing stabilized formal charges in their Lewis structure. The scope of three‐atom groupings possible in (3+2) cycloadditions can be greatly expanded by taking of advantage neutral three‐atom components (TACs). These groupings result in zwitterionic (3+2) cycloadducts adaptable to multiple outcomes depending on structure and conditions. Herein, the intramolecular (3+2) cycloaddition reaction between alkynyl sulfides (neutral TAC) and alkynes to provide key thiophenium ylide intermediates is first reported. These reactive species provide access to highly substituted fused thiophenes following predictable chemical sequences. Structural features on the obtained thiophenes were highly configurable by judicious choice of both alkynyl sulfide substitution and reaction conditions. [ABSTRACT FROM AUTHOR]

Leveraging of 1,5-hydride shift enabled diastereoselective hydroalkylation of aryl alkenes, allowing for construction of consecutive vicinal stereogenic centers in a single process. The transformation is triggered by electrophilic alkylation of aryl alkenes with in-situ generated carbocations, that is followed by diastereoselective 1,5-hydride shift to the resulting benzylic carbocation through a rigid 6-membered ring chair-like transition state. Image 1 [ABSTRACT FROM AUTHOR]

Gold catalysis is a convenient tool to oxidatively functionalize alkyne into a range of valuable compounds. In this article, we report a new access to isochroman-4-one and 2 H -pyran-3(6 H)-one derivatives that involves a gold-catalyzed oxidative cycloalkoxylation of an alkyne in the presence of a pyridine N -oxide. The reaction proceeds under mild conditions, is relatively efficient and exhibits a high functional group compatibility. [ABSTRACT FROM AUTHOR]

The article discusses gold catalyzed isomerisation of 5-en-2-yn-1-yl acetates. Treatment of propargylic acetate 4a with 1% of Ph3PAuNTf2 in CH2C12 at room temperature furnished the desired bicyclo[3.1.O]- hexene in 49% yield along with 41% of the postulated intermediate allene 5a. The reaction proved to be quite general and various substituted 5-en-2-yn-1-yl acetates 4b-j reacted using 1 % of 7 as the catalyst to furnish the corresponding bicyclo[3.1.0]hexenes 6b-j in generally good yields.

The article presents several chemical equations for benzene rings with more than 7 members including tandem cycloisomerization or cope rearrangement for syntheisis of Hydroazulenic Motif catalyzed with gold, published in a 2013 issue of the journal "Angewandte Chemie International Edition."

Review: 129 refs. [ABSTRACT FROM AUTHOR]

Direct C−H bond functionalization is a useful strategy for the straightforward formation of C−C and C−Heteroatom bonds. In the present work, a unique approach for the challenging electrophilic Au‐catalyzed α‐C−H bond functionalization of tertiary amines is presented. Electronic, steric and conformational synergistic effects exerted by the use of a malonate unit in the substrate were key to the success of this transformation. This new reactivity was applied to the synthesis of tetrahydro‐γ‐carboline products which, under oxidative conditions, could be converted into valuable structural motifs found in bioactive alkaloid natural products. [ABSTRACT FROM AUTHOR]

Direct C−H bond functionalization is a useful strategy for the straightforward formation of C−C and C−Heteroatom bonds. In the present work, a unique approach for the challenging electrophilic Au‐catalyzed α‐C−H bond functionalization of tertiary amines is presented. Electronic, steric and conformational synergistic effects exerted by the use of a malonate unit in the substrate were key to the success of this transformation. This new reactivity was applied to the synthesis of tetrahydro‐γ‐carboline products which, under oxidative conditions, could be converted into valuable structural motifs found in bioactive alkaloid natural products. [ABSTRACT FROM AUTHOR]

A new method for converting 2-alkynyl arylazide derivatives into functionalized polysubstituted quinolines following a gold-catalyzed 1,3-acetoxy shift/cyclization/1,2-group shift sequence has been developed. This transformation proceeds under mild reaction conditions, is efficient, and tolerates a large variety of functional groups. [ABSTRACT FROM AUTHOR]

A series of alkynyl ethers react with an electrophilic gold(I) catalyst to produce a range of structurally complex Spiro or fused dihydrofurans and dihydropyrans via a 1,5-hydride shift/cyclization sequence. This hydroalkylation process, which is performed under practical experimental conditions, can be applied to terminal as well as ester-substituted alkynes. It allows the efficient conversion of secondary or tertiary sp3 C-H bonds into new C-C bonds by the nucleophilic addition of a vinylgold species onto an oxonium intermediate. The stereoselectivity of the cycloisomerization process toward the formation of a new five- or six-membered cycle appears to be dependent on steric factors and the alkyne substitution pattern. [ABSTRACT FROM AUTHOR]

The bis-2,5-diphenylphosphole xantphos ligand (XDPP) 1 reacts with the [AuCl(tht)] complex to afford the monocoordinated [Au(XDPP)Cl] 2 and the dicoordinated chelate species [Au(XDPP)Cl] 3. Addition of AgOTf on this mixture, at room temperature, affords the cationic [Au(XDPP)][OTf] complex 4 which was fully characterized. An X-ray crystal structure analysis confirms the bent structure of this 14 VE [ML2]+ complex. Reaction of 4 with HSiMe2Ph in tetrahydrofuran at -78 °C yields the dinuclear [(XDPP)Au-H-Au(XDPP)]+ cationic complex 5, in which the hydride bridges the two [Au(XDPP)]+ metal fragments. In 5, the Au-P bond lengths are different and the phosphorus atoms which are located nearly trans to the hydride ligand exhibit significantly shorter P-Au bond lengths. Reaction of 4 with DSiMe2Ph to form the [(XDPP)Au-D-Au(XDPP)]+ complex 6 allowed to unambiguously ascribe the chemical shift of the deuteride in ²H NMR (δ = 7.0 ppm with a ²JDP = 8.4 Hz. The electronic structure of the [(XDPP)Au-H-Au(XDPP)]+ complex was studied through density functional theory calculations. An orbital analysis is developed in which complex 5 is viewed as the combination of two 12 electrons fragments [Au(XDPP)]+ with H-. This analysis reveals that the hydride interacts in a bonding way with the σ MO between the two gold atoms and in an antibonding way with a combination of d orbitals at the metal centers. This simple description allows to rationalize the inequivalence of the two types of P-Au bonds in 5. [ABSTRACT FROM AUTHOR]

Abstract: Diversely substituted 4-alkylidene-1,3-dioxolan-2-ones are efficiently synthesized by a gold(I)-catalyzed rearrangement of propargylic tert-butyl carbonates. The substrates are readily accessible and the transformation, which is performed under mild reaction conditions using a low loading of catalyst, allows the synthesis of cyclic carbonates, which would be less efficiently obtained using traditional methods. This procedure has also been applied to the stereoselective synthesis of (E)- or (Z)-4-halomethylene-1,3-dioxolan-2-ones, which proved to be suitable substrates for palladium-catalyzed cross-coupling reactions. [Copyright &y& Elsevier]

Abstract: Concise routes to aspidospermidine and 13-deoxyserratine are described, hinging on a cascade starting from an amidyl radical and allowing the construction of the key indolizidine cores in one step. [Copyright &y& Elsevier]

Gold‐catalyzed dehydro‐Diels‐Alder reactions of ynamide derivatives allow efficient access to a variety of N‐containing aromatic heterocycles. A dual gold catalysis mechanism was postulated for transformations involving the formation of C−C bonds by reaction between a terminal alkyne and an enynamide fragment. In this article, complete experimental and computational investigations into the mechanism of such a transformation are reported. Support for a dual gold catalysis was found and it was shown that the concerted or stepwise nature of the cyclization event depends on the substitution of the ynamide moiety. The reaction was found to proceed in three stages: 1) formation of a σ,π‐digold complex from the terminal alkyne, 2) cyclization to produce a gem‐diaurated aryl complex, and 3) catalyst transfer to free the product and regenerate the σ,π‐digold complex. [ABSTRACT FROM AUTHOR]

The use of [XPhosAu(NCMe)]SbF6in nitromethane at 100 °C allows the rapid and efficient formation of variously substituted dihydroquinolines, which can be subsequently converted into indoles by a rare photochemical rearrangement. [ABSTRACT FROM AUTHOR]

The article presents a study which focuses on how benzyl propargyl ethers react with the gold (I) catalyst in furnishing substituted allenes through the fragmentation sequence. It suggests that the transformation can be performed under mild conditions through terminals and substituted alkyne substrates. Moreover, it mentions that allenes can be reacted in situ with the nucleophile which corresponds to the overall reductive substitution process.

Abstract: A new protocol for the synthesis of a variety of N‐containing aromatic heterocycles by a formal gold‐catalyzed dehydro‐Diels–Alder reaction of ynamide derivatives has been developed. Deuterium‐labeling experiments and kinetic studies support the involvement of a dual gold catalysis mechanism in which a gold acetylide moiety adds onto an aurated keteneiminium. [ABSTRACT FROM AUTHOR]

Abstract: A new protocol for the synthesis of a variety of N‐containing aromatic heterocycles by a formal gold‐catalyzed dehydro‐Diels–Alder reaction of ynamide derivatives has been developed. Deuterium‐labeling experiments and kinetic studies support the involvement of a dual gold catalysis mechanism in which a gold acetylide moiety adds onto an aurated keteneiminium. [ABSTRACT FROM AUTHOR]

Abstract The synthesis of fluorinated synthetic intermediates has become a field of intense research in organic chemistry. In this article, we report the application of a gold-catalyzed rearrangement to the synthesis of β-trifluoromethylated α,β-unsaturated ketones. The scope of the reaction, as well as the valorization of the products in subsequent transformations has been investigated. This study allowed for the preparation of various CF 3 -substituted enones and fluorinated Diels-Alder adducts from easily accessible starting materials. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

A new protocol for the anti-Markovnikov hydrofunctionalization of alkenyl alcohol O-Bn ethers was developed using xanthates as functionalizing agents in the presence of lauroyl peroxide as a radical initiator and a stoichiometric oxidant. The benzyl group serves as a traceless hydrogen donor in the remote radical hydrogen atom transfer event during the process. [ABSTRACT FROM AUTHOR]

Abstract: A new protocol for the deoxygenation of alcohols and the hydrogenation of alkenes under Brønsted acid catalysis has been developed. The method is based on the use of either a benzyl or isopropyl ether as a traceless hydrogen‐atom donor, and involves an intramolecular hydride transfer as a key step, which is achieved in a regio‐ and stereoselective manner. [ABSTRACT FROM AUTHOR]

Abstract: A new protocol for the deoxygenation of alcohols and the hydrogenation of alkenes under Brønsted acid catalysis has been developed. The method is based on the use of either a benzyl or isopropyl ether as a traceless hydrogen‐atom donor, and involves an intramolecular hydride transfer as a key step, which is achieved in a regio‐ and stereoselective manner. [ABSTRACT FROM AUTHOR]

A protocol for the anti-Markovnikov hydrofunctionalization of alkenes has been developed by the use of a benzyl group as a traceless redox-active hydrogen donor. Under copper catalysis and in the presence of CF3- or N3-containing hypervalent iodine reagents, a series of homoallylic alcohol derivatives were hydrofunctionalized regioselectivity. A similar principle was also applied to the hydrofunctionalization of alkenols. [ABSTRACT FROM AUTHOR]

A protocol for the anti-Markovnikov hydrofunctionalization of alkenes has been developed by the use of a benzyl group as a traceless redox-active hydrogen donor. Under copper catalysis and in the presence of CF3- or N3-containing hypervalent iodine reagents, a series of homoallylic alcohol derivatives were hydrofunctionalized regioselectivity. A similar principle was also applied to the hydrofunctionalization of alkenols. [ABSTRACT FROM AUTHOR]

A new method for the synthesis of trifluoromethyl-allenes from easily accessible α-trifluoromethyl-propargyl benzyl ether derivatives following a gold-catalyzed intramolecular hydride transfer has been developed. Various di- and trisubstituted trifluoromethyl-allenes were obtained in good to excellent yields. [ABSTRACT FROM AUTHOR]

Review: [46 refs. [ABSTRACT FROM AUTHOR]

A novel gold-catalyzed method to convert 2-alkynyl arylazides into polysubstituted quinolines is developed. [ABSTRACT FROM AUTHOR]

2 H-Azirines are easily synthesized from the corresponding ketones and, despite possessing a CN bond embedded in a strained three-membered cycle, they are sufficiently stable to be isolated, stored, and manipulated. 2 H-Azirines can be regarded as valuable synthetic equivalents of alkenyl nitrenes, however, reactions capitalizing on the cyclic strain of the heterocyclic motif and involving the cleavage of the CN single bond remain surprisingly limited. A gold-catalyzed reaction that allows the formation of polysubstituted functionalized pyridines from easily accessible 2-propargyl 2H-azirine derivatives was developed. This transformation, which corresponds to an unprecedented intramolecular transfer of an alkenyl nitrene to an alkyne, proceeds with low catalyst loading, is efficient, and exhibits a high functional-group tolerance and a wide substrate scope. [ABSTRACT FROM AUTHOR]

2 H-Azirines are easily synthesized from the corresponding ketones and, despite possessing a CN bond embedded in a strained three-membered cycle, they are sufficiently stable to be isolated, stored, and manipulated. 2 H-Azirines can be regarded as valuable synthetic equivalents of alkenyl nitrenes, however, reactions capitalizing on the cyclic strain of the heterocyclic motif and involving the cleavage of the CN single bond remain surprisingly limited. A gold-catalyzed reaction that allows the formation of polysubstituted functionalized pyridines from easily accessible 2-propargyl 2H-azirine derivatives was developed. This transformation, which corresponds to an unprecedented intramolecular transfer of an alkenyl nitrene to an alkyne, proceeds with low catalyst loading, is efficient, and exhibits a high functional-group tolerance and a wide substrate scope. [ABSTRACT FROM AUTHOR]

A studyof the reaction of easily accessible 2-propynyloxy-6-fluoropyridineswith arylamines under gold or silver catalysis is described. It hasbeen shown that two types of isomeric oxazolopyridine imine derivatives,which represent unusual heterocyclic motifs, can be selectively obtainedin moderate to excellent yields depending on the nature of the metalemployed. [ABSTRACT FROM AUTHOR]

Let the sunshine in! Unactivated alkyl and aryl bromides underwent a light‐enabled reductive radical cyclization in the presence of a dimeric phosphine–gold complex as a photocatalyst (see scheme; X=C(CO2Et)2, NR, O). Sunlight can be used as the energy source for this simple and efficient radical reaction, which does not require potentially hazardous and toxic chemical reagents, such as organostannanes and chemical initiators. [ABSTRACT FROM AUTHOR]

Unaktivierte Alkyl ‐ und Arylbromide gehen eine reduktive radikalische Cyclisierung in Gegenwart eines dimeren Phosphan ‐ Gold ‐ Komplexes als Photokatalysator ein (siehe Schema; X=C(CO2Et)2, NR, O). Sonnenlicht kann als Energiequelle für diese einfache und effiziente Radikalreaktion genutzt werden, wodurch sich potenziell gefährliche und toxische chemische Reagentien wie Organostannane und chemische Initiatoren vermeiden lassen. [ABSTRACT FROM AUTHOR]

Striking gold: A series of variously functionalized propynyl arenes was smoothly converted into indan‐2‐ones by a new gold(I)‐catalyzed oxidative cyclization process. [LAu]NTf2 (Tf=trifluoromethanesulfonyl) is a superior catalyst both in terms of yield and kinetics for the present transformation. [ABSTRACT FROM AUTHOR]

Erstaunliches Gold: Eine Serie funktionalisierter Propinylarene wurde durch einen neuen, milden Gold(I) ‐ katalysierten oxidativen Cyclisierungsprozess in Indan ‐ 2 ‐ one umgewandelt. [LAu]NTf2 (Tf=Trifluormethansulfonyl) erwies sich als der beste Katalysator bezüglich Ausbeute und Reaktionskinetik. [ABSTRACT FROM AUTHOR]

Abstract: A study concerning the gold(I)-catalyzed transformation of N-(hex-5-enynyl) tert-butyloxycarbamates is described. The mild conditions employed allow the moderately efficient but stereoselective synthesis of a range of bicyclic carbamates following a formal [4+2] cycloaddition process. [Copyright &y& Elsevier]

The article presents chemical structure for divergent product selectivity in gold.

The article presents a chemical reaction for the synthesis of functionalized pyridines with the help of 2H-azirines.

A light-enabled reductive radical reaction of various unactivated alkyl and aryl bromides in the presence of a dimeric gold-phosphine complex as catalyst is described. [ABSTRACT FROM AUTHOR]

An abstract of the article "Biarylphosphonite Gold (I) Complexes as Superior Catalysts for Oxidative Cyclization of Propynyl Arenes into Indan-2-ones" by Guilhem Henrion and colleagues is presented.