A³-Coupling catalyzed by robust Au nanoparticles covalently bonded to HS-functionalized cellulose nanocrystalline films

• Jian-Lin Huang,
• Derek G. Gray and
• Chao-Jun Li

Beilstein J. Org. Chem. 2013, 9, 1388–1396, doi:10.3762/bjoc.9.155

• reaction; cellulose nanocrystallites (CNCs) films; gold catalysis; water or without solvent; Introduction Organic synthesis is usually performed in organic solvents; however, from a green chemistry perspective, evaporation and discharge of organic solvents not only generates chemical waste but also causes

• achieved in aqueous media or without solvent by gold catalysis [17][18][19]. However, up until now, most of the reactions are conducted by using homogenous organometallic catalysts. They usually show the high catalytic activity and selectivity [20]; however, homogeneous catalysts are difficult to adopt in

Gold-catalyzed intermolecular hydroamination of allenes with sulfonamides

• Chen Zhang,
• Shao-Qiao Zhang,
• Hua-Jun Cai and
• Dong-Mei Cui

Beilstein J. Org. Chem. 2013, 9, 1045–1050, doi:10.3762/bjoc.9.117

• the intermolecular hydroamination of allenes with sulfonamides is shown. The reaction proceeded smoothly under mild conditions for differently substituted allenes giving N-allylic sulfonamides in good yields with high regioselectivity and E-selectivity. Keywords: allene; gold catalysis

Gold-catalyzed oxycyclization of allenic carbamates: expeditious synthesis of 1,3-oxazin-2-ones

• Benito Alcaide,
• Pedro Almendros,
• M. Teresa Quirós and
• Israel Fernández

Beilstein J. Org. Chem. 2013, 9, 818–826, doi:10.3762/bjoc.9.93

• gold-catalyzed synthetic routes to 1,3-oxazinan-2-ones (kinetically controlled products) and 1,3-oxazin-2-one derivatives (thermodynamically favored) from easily accessible allenic carbamates has been carried out. Keywords: allenes; computational chemistry; gold; gold catalysis; heterocycles; reaction

Synthesis of axially chiral oxazoline–carbene ligands with an N-naphthyl framework and a study of their coordination with AuCl·SMe₂

• Feijun Wang,
• Shengke Li,
• Mingliang Qu,
• Mei-Xin Zhao,
• Lian-Jun Liu and
• Min Shi

Beilstein J. Org. Chem. 2012, 8, 726–731, doi:10.3762/bjoc.8.81

• , affording the corresponding Au(I) complexes in moderate to high yields. Keywords: axially chiral ligand; gold; N-heterocyclic carbenes; N-naphthyl framework; Introduction During the past decade, with an explosive growth of asymmetric homogeneous gold catalysis in C–C, C–O, or C–N bond formations, the

Access to pyrrolo-pyridines by gold-catalyzed hydroarylation of pyrroles tethered to terminal alkynes

• Elena Borsini,
• Gianluigi Broggini,
• Andrea Fasana,
• Chiara Baldassarri,
• Angelo M. Manzo and
• Alcide D. Perboni

Beilstein J. Org. Chem. 2011, 7, 1468–1474, doi:10.3762/bjoc.7.170

• -azepines. Keywords: C–C coupling; gold catalysis; homogeneous catalysis; nitrogen heterocycles; rearrangement; Introduction Intramolecular transition-metal-catalyzed reactions represent one of the most challenging routes for the preparation of heterocyclic compounds [1][2][3][4][5]. Methodologies

• chemists. Gold catalysis has recently emerged as a suitable way to achieve such a goal, mainly thanks to the chemoselective alkynophilic properties of this attractive metal in different types of reactions [6][7][8][9][10][11][12][13][14][15]. Among the hydroarylation reactions, various kinds of heteroaryl

• pyrrolo[2,3-c]pyridines (Scheme 1) [33]. The reaction provided also the isomeric pyrrolo[3,2-c]pyridines arising from 1,2-migration of the amide moiety. Having recently broadened our studies toward gold catalysis [34][35], we have been intrigued by the investigation of a gold-catalyzed intramolecular

Combination of gold catalysis and Selectfluor for the synthesis of fluorinated nitrogen heterocycles

• Antoine Simonneau,
• Pierre Garcia,
• Jean-Philippe Goddard,
• Virginie Mouriès-Mansuy,
• Max Malacria and
• Louis Fensterbank

Beilstein J. Org. Chem. 2011, 7, 1379–1386, doi:10.3762/bjoc.7.162

• the elucidation of the mechanism and Selectfluor was suggested to play the double role of promoting the oxidation of gold(I) to a gold(III) active species and also the electrophilic fluorination of the enamine intermediates. Keywords: cycloisomerization reactions; fluorinated pyrrolidines; gold

• catalysis; Selectfluor; Introduction The useful properties of fluorinated compounds in medicinal chemistry have motivated an intense effort towards the synthesis of new molecules bearing fluorine substituents [1][2]. Therefore, the development of a rapid access to C–F bonds is of great importance. Quite

Gold(I)-catalyzed synthesis of γ-vinylbutyrolactones by intramolecular oxaallylic alkylation with alcohols

• Michel Chiarucci,
• Mirko Locritani,
• Gianpiero Cera and
• Marco Bandini

Beilstein J. Org. Chem. 2011, 7, 1198–1204, doi:10.3762/bjoc.7.139

• tolerance make this catalytic process a promising route for the synthesis of architecturally complex polycyclic structures. Keywords: alcohol; butyrolactone; carbene; gold-catalysis; intramolecular oxaallylic alkylation; Introduction Allylic alcohols are highly desirable, readily available, cheap, and

Recent developments in gold-catalyzed cycloaddition reactions

• Fernando López and
• José L. Mascareñas

Beilstein J. Org. Chem. 2011, 7, 1075–1094, doi:10.3762/bjoc.7.124

• alternative procedure for the generation and subsequent cycloaddition of azomethine ylide intermediates under gold catalysis. Importantly, they demonstrated that the intramolecular attack of a nitrone oxygen to a tethered gold-activated alkyne leads, by means of an internal redox reaction, to an α-carbonyl

• related cycloaddition reactions. Indeed, the group of Toste described in 2007 a (2 + 2) intramolecular cycloaddition reaction between allenes and alkenes by gold catalysis [87]. The proposed mechanism is based on an activation of the allene to give a cationic metal species which undergoes a cyclization to

Asymmetric Au-catalyzed cycloisomerization of 1,6-enynes: An entry to bicyclo[4.1.0]heptene

• Alexandre Pradal,
• Chung-Meng Chao,
• Patrick Y. Toullec and
• Véronique Michelet

Beilstein J. Org. Chem. 2011, 7, 1021–1029, doi:10.3762/bjoc.7.116

• comprehensive study on gold-catalyzed enantioselective synthesis of bicyclo[4.1.0]heptenes, focusing on the scope and limitations of such systems. Results and Discussion Optimization of the catalytic system Based on our ongoing program on asymmetric gold catalysis [46][49][50][51][52], and on literature reports

Triazole–Au(I) complex as chemoselective catalyst in promoting propargyl ester rearrangements

• Dawei Wang,
• Yanwei Zhang,
• Rong Cai and
• Xiaodong Shi

Beilstein J. Org. Chem. 2011, 7, 1014–1020, doi:10.3762/bjoc.7.115

• . Keywords: allene; chemoselectivity; gold catalysis; ligand effect; organometallic; Introduction The past decade has seen rapid growth in the use of homogeneous gold catalysis for conducting powerful organic transformations [1][2][3][4][5][6][7][8][9]. Like many other transition metal complexes, the

• − were typically used. While the ligands (L) are certainly considered critical in gold catalysis, more and more attention have been paid to the evaluation of whether the choice of counter ligand “X” can be used to adjust the overall catalyst reactivity. The propargyl ester rearrangement was considered as

• significant challenge in gold catalysis. Results and Discussions Recently, our group reported the synthesis and characterization of the 1,2,3-triazole [36][37][38][39][40] coordinated gold(I) complexes. As revealed by the X-ray crystal structures (Scheme 3), both neutral and anionic triazoles can coordinate

One-pot Diels–Alder cycloaddition/gold(I)-catalyzed 6-endo-dig cyclization for the synthesis of the complex bicyclo[3.3.1]alkenone framework

• Boubacar Sow,
• Gabriel Bellavance,
• Francis Barabé and
• Louis Barriault

Beilstein J. Org. Chem. 2011, 7, 1007–1013, doi:10.3762/bjoc.7.114

• [3.3.1]alkanones in yields ranging from 48–93%. Keywords: bicyclo[3.3.1]nonenone; carbocyclization; Diels–Alder; gold catalysis; one-pot process; Introduction Highly oxygenated and densely substituted carbon-bridged medium sized rings such as 1 are commonly found in nature as structural frameworks of

Intramolecular hydroamination of alkynic sulfonamides catalyzed by a gold–triethynylphosphine complex: Construction of azepine frameworks by 7-exo-dig cyclization

• Hideto Ito,
• Tomoya Harada,
• Hirohisa Ohmiya and
• Masaya Sawamura

Beilstein J. Org. Chem. 2011, 7, 951–959, doi:10.3762/bjoc.7.106

• compounds. The protocol is applicable to the reaction of alkynic sulfonamides with an acyclic or ring-fused linker chain with various substitution patterns. Evaluation of the ligand effect in the gold catalysis with different ligands and substrates strongly suggested that the rate enhancement by the

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• compounds, ranging from pharmaceuticals and agrochemicals to advanced materials and polymers. Cationic gold acts as a soft and carbophilic Lewis acid and is considered one of the most powerful activators of C–C multiple bonds. Consequently, gold-catalysis plays an important role in the development of new

• 2008 to the present. Keywords: asymmetric addition; catalysis; gold; C−C multiple bonds; tandem reaction; Review 1 Introduction Gold-catalyzed reactions have emerged as a powerful synthetic tool in modern organic synthesis. This past decade has been the boom time for homogeneous gold catalysis, which

• studies have been selected to demonstrate the significance of gold catalysis. 2 Gold-catalyzed C–O bond formations The carbon–oxygen bond is one of the most widespread types of bonds in nature. Gold catalytic addition of oxygen nucleophiles to electronically non-activated C–C multiple bonds represents an

Gold(I)-catalyzed formation of furans by a Claisen-type rearrangement of ynenyl allyl ethers

• Florin M. Istrate and
• Fabien Gagosz

Beilstein J. Org. Chem. 2011, 7, 878–885, doi:10.3762/bjoc.7.100

• involves a Claisen-type rearrangement that allows the efficient creation of quaternary centers under mild experimental conditions. Keywords: Claisen rearrangement; furans; gold-catalysis; quaternary centers; Findings Furans represent an important class of heteroaromatic compounds, which are found in a

Gold-catalyzed propargylic substitutions: Scope and synthetic developments

• Olivier Debleds,
• Eric Gayon,
• Emmanuel Vrancken and
• Jean-Marc Campagne

Beilstein J. Org. Chem. 2011, 7, 866–877, doi:10.3762/bjoc.7.99

• mechanistic considerations. In this special issue dedicated to "Gold catalysis for organic synthesis", we would like to give a personal account on our work related to this topic: Scope, limitations and synthetic utilization of the gold(III)-catalyzed direct substitution of alcohols and the development of

• domino reactions. Review Gold-catalyzed alcohol substitution Scope and limitations In the past few years, homogeneous gold catalysis has emerged as an efficient tool to activate triple bonds for the addition of various nucleophiles to alkynes. We initially anticipated that, through coordination to π-bond

• interest and many efficient alternative methods were proposed [40][41][42][43]. Among these, great interest has been shown in the use of APTS or iron(III) catalysts due to their low cost and toxicity [26][27][28][29]. Despite its high cost, gold catalysis has some intrinsic benefits compared to other

Gold-catalyzed oxidation of arylallenes: Synthesis of quinoxalines and benzimidazoles

• Dong-Mei Cui,
• Dan-Wen Zhuang,
• Ying Chen and
• Chen Zhang

Beilstein J. Org. Chem. 2011, 7, 860–865, doi:10.3762/bjoc.7.98

• to form α-diketones and aldehydes in good yields is presented. Further directed synthesis of quinoxalines and benzimidazoles, via the condensation of the resulting α-diketones and aldehydes with benzene-1,2-diamine, was achieved in high yields. Keywords: allene; benzimidazole; gold-catalysis

When gold can do what iodine cannot do: A critical comparison

• Sara Hummel and
• Stefan F. Kirsch

Beilstein J. Org. Chem. 2011, 7, 847–859, doi:10.3762/bjoc.7.97

• Sara Hummel Stefan F. Kirsch Department Chemie and Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany 10.3762/bjoc.7.97 Abstract Gold catalysis has emerged as one of the most dynamic fields in organic synthesis. Only recently, more and more

• transformed into diverse product classes, depending on whether gold or iodonium activation was used to trigger the transformation. Since a comprehensive discussion on gold catalysis is not intended, the following examples of gold-catalyzed reactions simply illustrate certain prototype reactivity that i) is

• displays the possibility of diverse product creation through the use of either gold- or iodonium-triggered heterocyclizations. Carbocyclizations with 1,5-enynes Within the rapidly developing area of gold-catalysis, enyne cycloisomerizations have been particularly well studied [76][77][78][79][80][81][82

Au(I)/Au(III)-catalyzed Sonogashira-type reactions of functionalized terminal alkynes with arylboronic acids under mild conditions

• Deyun Qian and
• Junliang Zhang

Beilstein J. Org. Chem. 2011, 7, 808–812, doi:10.3762/bjoc.7.92

• mild conditions has been developed. Keywords: arylboronic acid; gold-catalysis; Sonogashira cross-coupling; Introduction The Sonogashira reaction has become the most important and widely used method for the synthesis of arylalkynes and conjugated enynes, which are precursors for natural products

• mild catalyst system. This chemistry strongly suggests the feasibility of Au(I) and Au(III) catalytic redox cycles, which would substantially broaden the field of gold catalysis and offer more functionalized products. Furthermore, the good tolerance toward many functional groups of substrates

High chemoselectivity in the phenol synthesis

• Matthias Rudolph,
• Melissa Q. McCreery,
• Wolfgang Frey and
• A. Stephen K. Hashmi

Beilstein J. Org. Chem. 2011, 7, 794–801, doi:10.3762/bjoc.7.90

• ; ketones; Introduction As documented in numerous reviews [1][2][3][4][5][6][7][8][9][10], over the last eleven years homogeneous gold catalysis has emerged from early examples [11][12] which documented its potential for organic synthesis of even complex molecules to an established tool in preparative

• organic chemistry [13][14]. One of these early examples is the gold-catalyzed phenol synthesis [12] in which the furan-ynes 1 used as substrates represent the first ene–yne-type compounds ever used in gold catalysis. While many investigations in the field focused on methodology, mechanistic research was

When cyclopropenes meet gold catalysts

• Frédéric Miege,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

• Frederic Miege Christophe Meyer Janine Cossy Laboratoire de Chimie Organique, ESPCI ParisTech, CNRS (UMR 7084), 10 rue Vauquelin 75231 Paris Cedex 05, France 10.3762/bjoc.7.82 Abstract Cyclopropenes as substrates entered the field of gold catalysis in 2008 and have proven to be valuable partners

• in a variety of gold-catalyzed reactions. The different contributions in this growing research area are summarized in this review. Keywords: cyclopropenes; gold carbenes; gold catalysis; gold-stabilized allylic cations; ring-opening; Review Introduction Homogeneous gold catalysis has become a

• bonds [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Whereas alkynes, alkenes and allenes have been widely used as substrates or partners in gold-catalyzed reactions, it was only rather recently, in 2008, that cyclopropenes entered the field of gold catalysis despite their well-known high and

Gold-catalyzed alkylation of silyl enol ethers with ortho-alkynylbenzoic acid esters

• Haruo Aikawa,
• Tetsuro Kaneko,
• Naoki Asao and
• Yoshinori Yamamoto

Beilstein J. Org. Chem. 2011, 7, 648–652, doi:10.3762/bjoc.7.76

• -induced in situ construction of leaving groups and subsequent nucleophilic attack on the silyl enol ethers. The generated leaving compound abstracts a proton to regenerate the silyl enol ether structure. Keywords: alkylation; gold catalysis; leaving group; silyl enol ether; substitution reaction

Sequential Au(I)-catalyzed reaction of water with o-acetylenyl-substituted phenyldiazoacetates

• Lei Zhou,
• Yizhou Liu,
• Yan Zhang and
• Jianbo Wang

Beilstein J. Org. Chem. 2011, 7, 631–637, doi:10.3762/bjoc.7.74

• steps. Keywords: alkyne; carbene O–H insertion; cyclization; diazo compounds; gold catalysis; 1H-isochromene; Introduction Transition metal carbene complexes are versatile intermediates and can undergo diverse transformations, including X–H (X = C, O, S, N, etc.) insertions, cyclopropanations, ylide

Construction of cyclic enones via gold-catalyzed oxygen transfer reactions

• Leping Liu,
• Bo Xu and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2011, 7, 606–614, doi:10.3762/bjoc.7.71

• increased substantially and gold catalysis has become one of the hottest research fields in synthetic organic chemistry [34][35][36][37][38][39][40][41][42]. Due to their unique alkynophilicity, gold catalysts are especially suited to the activation of carbon–carbon triple bonds. Gold-catalyzed formation of

Gold-catalyzed regioselective oxidation of terminal allenes: formation of α-methanesulfonyloxy methyl ketones

• Yingdong Luo,
• Guozhu Zhang,
• Erik S. Hwang,
• Thomas A. Wilcoxon and
• Liming Zhang

Beilstein J. Org. Chem. 2011, 7, 596–600, doi:10.3762/bjoc.7.69

• ; gold; oxidation; regioselectivity; Introduction While alkynes are the most studied substrates in homogeneous gold catalysis [1][2][3][4][5][6][7][8][9], allenes [10] occupy a not-so-distant second place, and many versatile transformations have been developed either using allenes as substrates [11][12

Gold catalysis for organic synthesis

• F. Dean Toste

Beilstein J. Org. Chem. 2011, 7, 553–554, doi:10.3762/bjoc.7.63

• from 13 countries underscore the growing importance of homogenous gold catalysis. More importantly, the papers in this Thematic Series highlight the remarkable breath of reactivity that can be accessed using homogenous gold complexes as catalysts; from catalysis of sigmatropic rearrangement