Synthesis of 1,2-divinylcyclopropanes by metal-catalyzed cyclopropanation of 1,3-dienes with cyclopropenes as vinyl carbene precursors

• Jesús González,
• Alba de la Fuente,
• María J. González,
• Laura Díez de Tejada,
• Luis A. López and
• Rubén Vicente

Beilstein J. Org. Chem. 2019, 15, 285–290, doi:10.3762/bjoc.15.25

• example of isolation of these structures. Indeed, Lee and co-worker found that the corresponding gold-catalyzed reaction leads to ring-opened products through a facile oxy-Cope-rearrangement [28]. Moreover, these structures are also not accessible with metal–vinyl carbenes generated from vinyldiazo

Gold-catalyzed ethylene cyclopropanation

• Silvia G. Rull,
• Andrea Olmos and
• Pedro J. Pérez

Beilstein J. Org. Chem. 2019, 15, 67–71, doi:10.3762/bjoc.15.7

• cyclopropanecarboxylates. Routes toward ethyl cyclopropanecarboxylate (1). (a) Ethylene cyclopropanation described by De Bruin and co-workers as secondary reaction. (b) Stoichiometric transformations. (c) Gold-catalyzed ethylene cyclopropanation described in this work. Catalyst screening for the reaction of ethylene and

Gold-catalyzed post-Ugi alkyne hydroarylation for the synthesis of 2-quinolones

• Xiaochen Du,
• Jianjun Huang,
• Anton A. Nechaev,
• Ruwei Yao,
• Jing Gong,
• Erik V. Van der Eycken,
• Olga P. Pereshivko and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2018, 14, 2572–2579, doi:10.3762/bjoc.14.234

• . Subjecting these adducts to a gold-catalyzed intramolecular alkyne hydroarylation process allowed to efficiently construct the 2-quinolone core bearing a branched substituent on the nitrogen atom. Keywords: gold catalysis; hydroarylation; 2-quinolones; Ugi reaction; Introduction Quinoline and its oxidized

• nitrogen atom through an intramolecular gold-catalyzed alkyne hydroarylation reaction (Scheme 2). It should be noted, that heterocyclic syntheses through post-Ugi transformations have been under extensive exploration for the last two decades [47][48][49], especially in terms of gold-catalyzed Friedel

• 6a gave moderate results for the Ugi reaction and good to excellent efficiency for the gold-catalyzed cyclization (Figure 1, products 8a–c). As for the aldehyde component 4, both (hetero)aromatic and aliphatic ones were found to be tolerable (Figure 1, products 8d–k), although for the electron

Synthesis of indolo[1,2-c]quinazolines from 2-alkynylaniline derivatives through Pd-catalyzed indole formation/cyclization with N,N-dimethylformamide dimethyl acetal

• Antonio Arcadi,
• Sandro Cacchi,
• Giancarlo Fabrizi,
• Francesca Ghirga,
• Antonella Goggiamani,
• Antonia Iazzetti and
• Fabio Marinelli

Beilstein J. Org. Chem. 2018, 14, 2411–2417, doi:10.3762/bjoc.14.218

• palladium-catalyzed reaction of 15a in the presence of DMFDMA led directly to the formation of quinazoline 13a in 71% yield through a sequential process (Scheme 5a). The selective formation of products 13 from 15 (and also from 3-unsubstituted indoles 14) is not trivial, since the previously reported gold

• -catalyzed reaction of 15a with aldehydes as electrophiles resulted in the divergent formation of 11H-indolo[3,2-c]quinolines 17 (Scheme 5b) [32] through functionalization of C-3 position of the indole ring instead of N-1. The sequential reaction shown in Scheme 5, path a, probably occurs through cyclization

Anomeric modification of carbohydrates using the Mitsunobu reaction

• Julia Hain,
• Patrick Rollin,
• Werner Klaffke and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2018, 14, 1619–1636, doi:10.3762/bjoc.14.138

• carbocyclic lignan variants related to podophyllotoxin, a pseudo-anomeric stereospecific inversion of a carbasugar was achieved in good yield in Nishimura’s group [39]. More recently, the Mitsunobu procedure was applied in the context of gold-catalyzed glycosylation in order to install a reactive anomeric

AuBr₃-catalyzed azidation of per-O-acetylated and per-O-benzoylated sugars

• Jayashree Rajput,
• Srinivas Hotha and
• Madhuri Vangala

Beilstein J. Org. Chem. 2018, 14, 682–687, doi:10.3762/bjoc.14.56

• ]. Thus, various research groups employed either a remote alkyne group possessing versatile glycosyl donors [7][8][9][10][11][12][13][14][15][16] or used glycals [17] for effective O-, C-, and S-glycosylation reactions using gold(I) and gold(III) catalysts. Among the gold-catalyzed activation of non

• -alkynic glycosyl donors, glycosyl halides [18], armed O-methyl glycosides [19], armed and disarmed thioglycosides [20] as well as trichloroacetimidate [21][22] donors were successfully applied to O- and C-glycosylations. Of the gold-catalyzed N-glycosylation reactions, Yu et al. demonstrated the effective

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

• Matthias Wünsch,
• David Schröder,
• Tanja Fröhr,
• Lisa Teichmann,
• Sebastian Hedwig,
• Nils Janson,
• Clara Belu,
• Jasmin Simon,
• Shari Heidemeyer,
• Philipp Holtkamp,
• Jens Rudlof,
• Lennard Klemme,
• Alessa Hinzmann,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2017, 13, 2428–2441, doi:10.3762/bjoc.13.240

• ], gold-catalyzed azetidin-3-one formation [16], as well as various transition metal-mediated additions and cross-coupling reactions [17] represent further important reactions of propargylamines, providing the potential to form innovative peptidomimetics (Figure 2). Our attention has been focused on the

• ) Intramolecular Pauson–Khand reaction, R = (S)-tert-butylsulfinyl, R’ = CH2CH2OTBDPS [14]. b) Diels–Alder reaction, R = pTs, R’ = H, R’’ = Me [15]. c) Gold-catalyzed intramolecular reaction to azetidin-3-ones, R = tert-butylsulfonyl, R’ = aromatics, aliphatics [16]. d) Sonogashira cross-coupling, R = tert

A practical and efficient approach to imidazo[1,2-a]pyridine-fused isoquinolines through the post-GBB transformation strategy

• Taofeng Shao,
• Zhiming Gong,
• Tianyi Su,
• Wei Hao and
• Chao Che

Beilstein J. Org. Chem. 2017, 13, 817–824, doi:10.3762/bjoc.13.82

• synthesis of the biologically intriguing imidazo[1,2-a]pyridine-fused isoquinoline systems from readily available starting materials was achieved through the Groebke–Blackburn–Bienaymé reaction followed by a gold-catalyzed cyclization strategy. The synthetic approach is characterized by mild reaction

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

Synthesis of 2-substituted tetraphenylenes via transition-metal-catalyzed derivatization of tetraphenylene

• Shulei Pan,
• Hang Jiang,
• Yanghui Zhang,
• Yu Zhang and
• Dushen Chen

Beilstein J. Org. Chem. 2016, 12, 1302–1308, doi:10.3762/bjoc.12.122

• acetoxylation a highly interesting reaction. The Sanford and Wang group, respectively, developed a highly efficient palladium and gold-catalyzed direct acetoxylation of arenes with iodobenzene diacetate [48][49]. Based on these excellent works, we surveyed the reaction conditions for the acetoxylation of

• halogenation of tetraphenylene attracted our attention. The Wang group reported an efficient and mild protocol for a gold-catalyzed direct C–H halogenation of arenes with N-halosuccinimides [56][57]. Therefore, we initially investigated the chlorination of tetraphenylene by subjecting it to Wang’s conditions

Gold-catalyzed direct alkynylation of tryptophan in peptides using TIPS-EBX

• Gergely L. Tolnai,
• Jonathan P. Brand and
• Jerome Waser

Beilstein J. Org. Chem. 2016, 12, 745–749, doi:10.3762/bjoc.12.74

• is highly attractive, but the use of a carbon linker is usually required. Herein, we report the gold-catalyzed direct alkynylation of tryptophan in peptides using the hypervalent iodine reagent TIPS-EBX (1-[(triisopropylsilyl)ethynyl]-1,2-benziodoxol-3(1H)-one). The reaction proceeded in 50–78% yield

• . Conclusion In conclusion, our work combined with the results of Hansen and co-workers has demonstrated that the gold-catalyzed alkynylation of indoles could be extended to tryptophan in peptides. When considering the scarcity of methods allowing the modification of tryptophan under mild conditions without

• -compatible reagents and catalysts. Experimental General procedure for the gold-catalyzed alkynylation The starting peptide 4 (0.20 mmol, 1 equiv) and TIPS-EBX (1a, 0.240 mmol, 103 mg, 1.2 equiv) were added into a 5 mL test tube equipped with a stirring bar. Acetonitrile (2 mL) was added, then the reaction

Study on the synthesis of the cyclopenta[f]indole core of raputindole A

• Nils Marsch,
• Mario Kock and
• Thomas Lindel

Beilstein J. Org. Chem. 2016, 12, 334–342, doi:10.3762/bjoc.12.36

• which provided the hydrogenated tricyclic cyclopenta[f]indole core system in high yield. Keywords: gold-catalyzed reactions; heterocycles; indole alkaloids; natural products; synthesis; Introduction The raputindoles (1, raputindole A, Figure 1) from the rutaceous tree Raputia simulans Kallunki

Pyridylidene ligand facilitates gold-catalyzed oxidative C–H arylation of heterocycles

• Kazuhiro Hata,
• Hideto Ito,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2015, 11, 2737–2746, doi:10.3762/bjoc.11.295

• University, Chikusa, Nagoya 464-8602, Japan 10.3762/bjoc.11.295 Abstract Triaryl-2-pyridylidene effectively facilitates the gold-catalyzed oxidative C–H arylation of heteroarenes with arylsilanes as a unique electron-donating ligand on gold. The employment of the 2-pyridylidene ligand, which is one of the

• -catalyzed reactions, phosphines, N-heterocyclic carbenes, pyridines and salen ligands have been applied as ligands for controlling the stability of catalysts, and chemo-, regio- and enantioselectivities of the reactions [31][32][33][34][35][36]. Recent advances in the gold-catalyzed reactions are

• elegant works of Lloyd-Jones and Russell on gold-catalyzed oxidative C–H arylation of simple arenes with arylsilanes have led the way to novel gold-catalyzed reactions that could not be achieved with other transition metals [68][69]. In these reactions, the oxidation of gold(I) to gold(III) is thought to

Gold-catalyzed formation of pyrrolo- and indolo-oxazin-1-one derivatives: The key structure of some marine natural products

• Sultan Taskaya,
• Nurettin Menges and
• Metin Balci

Beilstein J. Org. Chem. 2015, 11, 897–905, doi:10.3762/bjoc.11.101

• hemiacetals after cascade reactions. Keywords: alkyne cyclization; gold-catalyzed reaction; indolo-oxazin-1-one; marine natural products; pyrrolo-oxazin-1-one; Introduction Pyrrole-containing heterocycles are widely distributed within a large number of natural products and biologically active molecules [1

• atom-economic process using a gold-catalyzed alkyne cyclization reaction as the key step. Pyrrole and indole, bearing one (substituted) propargyl and carboxy group was initially designed as model substrate for the construction of 6 and 7. Gold-catalyzed intramolecular cyclization of enyene carboxylic

• reaction we used a palladium catalyst and a copper(I) cocatalyst in the presence of triphenylphosphine and triethylamine as the base. The carboxylic acids were then submitted to a gold-catalyzed cyclization reaction (Table 2). The optimized reaction conditions for cyclization was employed for pyrrole- and

C–H-Functionalization logic guides the synthesis of a carbacyclopamine analog

• Sebastian Rabe,
• Johann Moschner,
• Marina Bantzi,
• Philipp Heretsch and
• Athanassios Giannis

Beilstein J. Org. Chem. 2014, 10, 1564–1569, doi:10.3762/bjoc.10.161

• was thought to establish the C-nor-D-homo steroid system, and a gold-catalyzed amination/annulation/aromatization sequence was planned to install the pyridine F-ring. Diazo compound 3 originates from diene 4 through standard transformations, the latter being accessible from commercially available and

• product 13 by chromatography was then achieved after selective hydrogenation of only the exocyclic olefin in 14 (H2, cat. Rh/C, EtOAc, 25 °C, structure of hydrogenation product not shown) employing the mixture of the isomers 13 and 14 from the previous step. Finally, a gold-catalyzed amination/annulation

A tandem Mannich addition–palladium catalyzed ring-closing route toward 4-substituted-3(2H)-furanones

• Jubi John,
• Eliza Târcoveanu,
• Peter G. Jones and
• Henning Hopf

Beilstein J. Org. Chem. 2014, 10, 1462–1470, doi:10.3762/bjoc.10.150

• towards 4-substituted-furanones from imines [41]. Recently Fructos et al. have shown that N-p-toluenesulfonyl-protected imines were better candidates for gold catalyzed Mannich addition of acetoacetates when compared to N-Boc (tert-butoxycarbonyl) and N-PMP (p-methoxyphenyl) imines [42]. Hence, we

Rapid pseudo five-component synthesis of intensively blue luminescent 2,5-di(hetero)arylfurans via a Sonogashira–Glaser cyclization sequence

• Fabian Klukas,
• Alexander Grunwald,
• Franziska Menschel and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2014, 10, 672–679, doi:10.3762/bjoc.10.60

• . 2,5-dihalogenated furans can be in principle employed in cross-coupling reactions, however, the poor stability of these dihalogenated precursors renders this approach very tedious [29]. Recent publications report gold-catalyzed syntheses of di(hetero)arylfurans starting from arylbutadiynes [30][31

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

• three-coordinated -[Ag(NO2)]-L- chains, linked together by hydrogen bonds. The complex demonstrated to be more suited to aliphatic than aromatic aldehydes, whereas the presence of an EWG on the aldehyde resulted in low reaction yields. Gold catalysis The first example of a gold-catalyzed synthesis of

• years the development of new and effective nanostructured catalytic systems dominated the gold-catalyzed approach to A3-coupling. For example, ultrasmall gold(0) nanoparticles embedded in a mesoporous carbon nitride stabilizer [27] proved to be a highly active, selective and recyclable heterogeneous

• corresponding propargylamines 7 containing a quaternary carbon center [37] (Scheme 8). Aliphatic alkynes and acyclic amines gave the corresponding products in low yields, whereas the methodology was ineffective for aromatic ketones. Gold-catalyzed A3-MCRs were also applied with the aim to functionalize

Aminofluorination of 2-alkynylanilines: a Au-catalyzed entry to fluorinated indoles

• Antonio Arcadi,
• Emanuela Pietropaolo,
• Antonello Alvino and
• Véronique Michelet

Beilstein J. Org. Chem. 2014, 10, 449–458, doi:10.3762/bjoc.10.42

• Paris, UMR 8247, Ecole Nationale Supérieure de Chimie de Paris, Chimie ParisTech, 11 rue P. et M. Curie, F-75231 Paris Cedex 05, France 10.3762/bjoc.10.42 Abstract The scope and limitations of gold-catalyzed tandem cycloisomerization/fluorination reactions of unprotected 2-alkynylanilines to have

• wish to report herein a comprehensive study on gold-catalyzed tandem cycloisomerization/fluorination reactions to access 3,3-difluoro-2-aryl-3H-indoles and 3-fluoro-2-arylindoles, putting the stress on the scope and limitations of such systems. Results and Discussion Optimization of the catalytic

• reported to increase the yield of fluorination in the 5-position of mono- and nonbrominated 2-acylpyrroles with Selectfluor under microwave conditions [44]. The presence of larger amounts of water may nevertheless speed up the protodeauration of the indolylgold species derived from the gold-catalyzed

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• as the corresponding bis-zinc-enolate species. DVCPR occurred at ambient temperature, final acidic workup provided cycloheptadione 247 in excellent yield (see Scheme 31). Toste and coworkers [203] reported a tandem gold-catalyzed Claisen rearrangement from popargyl vinyl ether 248 (see Scheme 32) to

• . Toste and coworkers [205] discovered a 1,2-pivaloyl shift and cyclopropanation of the resulting gold-carbenoid from 258 with enyne 259 to yield vinylalkynecyclopropane 260. This compound was shown to undergo a gold catalyzed DVCPR to yield 261. Note that this reaction does most likely proceed via a step

• organoiron route towards the guianolide skeleton. Stoltz’s tandem Wolff/DVCPR rearrangement. Stephenson’s tandem photocatalysis/arylvinylcyclopropane rearrangement. Padwa’s rhodium cascade involving a DVCPR. Matsubara’s version of a DVCPR. Toste’s tandem gold-catalyzed Claisen-rearrangement/DVCPR. Ruthenium

Gold(I)-catalyzed domino cyclization for the synthesis of polyaromatic heterocycles

• Mathieu Morin,
• Patrick Levesque and
• Louis Barriault

Beilstein J. Org. Chem. 2013, 9, 2625–2628, doi:10.3762/bjoc.9.297

• ) to give the desired cyclized product 12. Structure of senaequidolide (13) and ellipticine (14). Gold(I)-catalyzed carbocyclization. Proposed mechanism for the gold(I)-catalyzed cyclization. Gold-catalyzed 5-exo-dig carbocyclization cascade. Supporting Information Supporting Information File 498

New developments in gold-catalyzed manipulation of inactivated alkenes

• Michel Chiarucci and
• Marco Bandini

Beilstein J. Org. Chem. 2013, 9, 2586–2614, doi:10.3762/bjoc.9.294

• toward a number of complexity-oriented transformations. In this segment, gold-catalyzed addition of carbon- and heteroatom-based nucleophiles to inactivated alkenes are widely recognized as “capricious” transformations due to alkyne and allene counterparts [1][2][3][4][5]. However, over the past few

• years, tremendous developments were made, and some of the major contributes will be summarized in the present review. Mechanistically, it is generally accepted that the gold-catalyzed nucleophilic addition to alkenes proceeds through three elementary steps: i) activation of the C–C double bond by gold

• eliminative pathway for the cleavage of the C–Au bond in the intermediate 1 (Figure 2, path b). This reaction channel is accessible under mild conditions and without external activation when proper gold catalysts are employed [7][8]. Furthermore, in recent years, advances in the gold-catalyzed

Stereodivergent synthesis of jaspine B and its isomers using a carbohydrate-derived alkoxyallene as C₃-building block

• Volker M. Schmiedel,
• Stefano Stefani and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2013, 9, 2564–2569, doi:10.3762/bjoc.9.291

• therefore leads to a stereodivergent approach to the natural product and its enantiomer. The gold-catalyzed 5-endo-cyclization affords the corresponding dihydrofurans, which after separation, azidation of the enol ether moiety and two subsequent reduction steps give the natural product and its stereoisomers

Ambient gold-catalyzed O-vinylation of cyclic 1,3-diketone: A vinyl ether synthesis

• Yumeng Xi,
• Boliang Dong and
• Xiaodong Shi

Beilstein J. Org. Chem. 2013, 9, 2537–2543, doi:10.3762/bjoc.9.288

• Yumeng Xi Boliang Dong Xiaodong Shi C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States 10.3762/bjoc.9.288 Abstract Gold-catalyzed O-vinylation of cyclic 1,3-diketones has been achieved for the first time, which provides direct

• as essential tools in organic synthesis. Generally with the unique reactivity and mild reaction conditions, this type of transformation has found widespread applications in complex molecule synthesis [10][11]. Among those reactions, the gold-catalyzed hydration of alkynes is regarded as one of the

• cross-coupling reactions [18]. Based on the π-carbophilicity of gold(I), the addition of alcohol to alkyne should provide direct access to the corresponding vinyl ether. However, most of the reported gold-catalyzed O-nucleophile additions to alkynes are intramolecular reactions. No general protocol for

Synthetic scope and DFT analysis of the chiral binap–gold(I) complex-catalyzed 1,3-dipolar cycloaddition of azlactones with alkenes

• María Martín-Rodríguez,
• Luis M. Castelló,
• Carmen Nájera,
• José M. Sansano,
• Olatz Larrañaga,
• Abel de Cózar and
• Fernando P. Cossío

Beilstein J. Org. Chem. 2013, 9, 2422–2433, doi:10.3762/bjoc.9.280

• base (Figure 1) [18][19]. This catalytic system was very effective but the reactions performed with (R)-Binap(AuOBz)2 (Figure 1) as catalyst offered a very low enantioselection, for example, a 8% ee was achieved in the 1,3-DC of alanine derived azlactone and N-phenylmaleimide (NPM). Numerous gold

• -catalyzed transformations employing mild reaction conditions appeared during the last twelve years [20][21][22]. Initially, coordination arrangements of chiral gold complexes avoided high enantiodiscriminations but, recently, it has been demonstrated that chiral bis-gold complexes type 2 (Figure 1) are very