Gold-catalyzed reaction of oxabicyclic alkenes with electron-deficient terminal alkynes to produce acrylate derivatives

• Yin-wei Sun,
• Qin Xu and
• Min Shi

Beilstein J. Org. Chem. 2013, 9, 1969–1976, doi:10.3762/bjoc.9.233

• (I) phosphane complexes with dialkylbiarylphosphane ligands (Figure 1) by using AgSbF6 as an additive and toluene as a solvent. No reaction occurred when gold(I) phosphane complexes 8–10 (Figure 1) were used as catalysts under identical conditions (Table 2, entries 2–4). Furthermore, the usage of

• gold(I) phosphane complexes 7, 11, 13 and 14 (Figure 1) as catalysts gave 3a in 10–29% yields (Table 2, entries 1, 5, 7 and 8). Gold complex 12 (Figure 1) with an electron-rich biphenylphosphine ligand was identified as the best catalyst, giving 3a in 67% yield (Table 2, entry 6). We attempted to

• into the reaction system, 3a was obtained in only 10% yield (Table 1, entry 23). Since the yield of 3a was still low, we next tried to improve the yield of 3a by deploying different ligands, Ag salts, solvents and temperature. The results are summarized in Table 2. At first, we examined many other gold

Gold-catalyzed regioselective oxidation of propargylic carboxylates: a reliable access to α-carboxy-α,β-unsaturated ketones/aldehydes

• Kegong Ji,
• Jonathan Nelson and
• Liming Zhang

Beilstein J. Org. Chem. 2013, 9, 1925–1930, doi:10.3762/bjoc.9.227

• could reach >200:1 by using the gold(I) catalyst derived from our previously developed bulky P,S-bidentate ligand L1 (Figure 1) [11]. A similarly high selectivity was also achieved by using the P,N-bidentate ligand Mor-DalPhos [36][37]. However, the Z/E ratios of 5a-OAc in the former case is ~13:1

Gold(I)-catalysed one-pot synthesis of chromans using allylic alcohols and phenols

• Eloi Coutant,
• Paul C. Young,
• Graeme Barker and
• Ai-Lan Lee

Beilstein J. Org. Chem. 2013, 9, 1797–1806, doi:10.3762/bjoc.9.209

• Eloi Coutant Paul C. Young Graeme Barker Ai-Lan Lee Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, EH14 1LP, United Kingdom 10.3762/bjoc.9.209 Abstract A gold(I)-catalysed reaction of allylic alcohols and phenols produces chromans regioselectively via a one-pot Friedel–Crafts

• have recently shown that gold(I) can catalyse a direct allylic etherification [52][53][54][55][56][57][58][59] of unactivated alcohols 2 with unactivated allylic alcohols 1 (Scheme 1, reaction 1) [60][61]. The reaction is mild, regioselective, and produces only water as a byproduct. During our studies

• , entries 4 and 5). Pleasingly however, lower equivalents of phenol are tolerated if the temperature is increased to 60 °C (Table 1, entries 6 and 7). In order to ascertain if the gold(I) catalyst is really necessary for the formation of chroman 8, several control reactions were carried out (Table 1

Gold(I)-catalyzed formation of furans from γ-acyloxyalkynyl ketones

• Marie Hoffmann,
• Solène Miaskiewicz,
• Jean-Marc Weibel,
• Patrick Pale and
• Aurélien Blanc

Beilstein J. Org. Chem. 2013, 9, 1774–1780, doi:10.3762/bjoc.9.206

• -acyloxyalkynyl ketones were efficiently converted into highly substituted furans with 2.5 mol % of triflimide (triphenylphosphine)gold(I) as a catalyst in dichloroethane at 70 °C. Keywords: alkynyl ketones; cycloisomerization; furans; gold-catalysis; 1,2-migration; Introduction Furans are an important class of

• catalysts with their carbophilic character have emerged as a new tool for furan preparation. As summarized in Scheme 1, furans could now be obtained by either gold(I) or gold(III) catalysis from various types of substrates such as allenyl ketones [8][9][10][11][12][13][14], enynes or diynes [15][16][17

• yields. We herein report that gold(I) can overcome these limitations, providing a general, fast and very efficient transformation of γ-acyloxyalkynyl ketones into trisubstituted and functionalized furans. Results and Discussion In order to find the most appropriate conditions, we applied various gold

Gold-catalyzed cyclization of allenyl acetal derivatives

• Dhananjayan Vasu,
• Samir Kundlik Pawar and
• Rai-Shung Liu

Beilstein J. Org. Chem. 2013, 9, 1751–1756, doi:10.3762/bjoc.9.202

• . Experimental General procedure for the gold-catalyzed carbocyclization General procedure for the the gold(I)-catalyzed carbocyclization of vinylallenyl acetal: A two-necked flask was charged with chloro(triphenylphosphine)gold(I) (11.1 mg, 0.022 mmol) and silver triflate (5.8 mg, 0.022 mmol), and to this

• silica bed. The solvent was evaporated under reduced pressure. The crude product was eluted through a short silica column (3% ethyl acetate in hexane) to afford the desired ketone 4a (70.6 mg, 0.40 mmol, 89%) as a pale yellow oil. General procedure for the gold(I)-catalyzed carbocyclization of

• propargylic ester acetals: Chloro(triphenylphosphine)gold(I) (8.0 mg, 0.016 mmol) and silver triflate (4.2 mg, 0.016 mmol) were added to a dried Schlenk tube under an N2 atmosphere, and freshly distilled CH2Cl2 (1.0 mL) was introduced by a syringe. The resulting mixture was stirred at room temperature for 10

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

• hydroamination, many require extreme and extended reaction conditions. Thus, development of these reactions is still needed. Recently, Yamamoto and co-workers reported the Pd(0)-catalyzed intermolecular hydroamination of allenes with sulfonamides [25]. In this paper, we wish to develop a gold(I)-complex

• shown in Scheme 1 [2][7][29][30][31][32][33][34][35][36]. The gold cation coordinated with allene to form cationic Au(I)-allene complex A, and this leads to cationic gold(I) complex B. The sulfonamide attacks at the less-substituted terminus of intermediate B to form C. Protonolysis of the Au–C bond of

Alkyne hydroarylation with Au N-heterocyclic carbene catalysts

• Cristina Tubaro,
• Marco Baron,
• Andrea Biffis and
• Marino Basato

Beilstein J. Org. Chem. 2013, 9, 246–253, doi:10.3762/bjoc.9.29

• the intermolecular hydroarylation of alkynes with simple unfunctionalised arenes. Both mono- and dinuclear gold(III) complexes were able to catalyze the reaction; however, the best results were obtained with the mononuclear gold(I) complex IPrAuCl. This complex, activated with one equivalent of silver

• the use of gold species as catalysts for alkyne hydroarylation is still quite limited. A substantial number of reports on the intramolecular cyclisation of arenes with tethered alkyne moieties using gold(I) or, to a lesser extent, gold(III) catalysts can be found in the literature [35][36][37][38][39

• few exceptions [36][40][44]. Finally, concerning the nature of the employed catalysts, simple gold salts or phosphino complexes of gold(I) were utilized in the majority of cases, although in recent years an increasing number of studies have been dealing with the application of NHC complexes of gold

On the proposed structures and stereocontrolled synthesis of the cephalosporolides

• Sami F. Tlais and
• Gregory B. Dudley

Beilstein J. Org. Chem. 2012, 8, 1287–1292, doi:10.3762/bjoc.8.146

• silyl ether 19 with the (R)-propylene oxide produced the internal alkyne 20 (Scheme 5). Gold(I) chloride in MeOH induced the spiroketalization of alkyne 20 with concomitant cleavage of the PMP acetal and partial cleavage of the TBS ether. After completion of the desilylation with TBAF, a mixture of 5,5

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

• diaminocarbene) gold(I) complexes 3 derived from 3,3′-substituted 1,1′-binaphthalenyl-2,2′-diamine, and their application in the dynamic kinetic asymmetric transformation of propargyl esters, giving the corresponding substituted chromenes in up to 99% ee [12]. Our group also developed a new family of axially

• )–C(7) = 173.12(16)° suggests a nearly linear coordination geometry around the gold(I) center, which is also a typical feature for known gold(I) complexes. Moreover, no coordinated oxazoline group in the complexes (Sa,S)-16 and (Ra,S)-16 could be further coordinated with other metal atoms such as Pd

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• absorption band at 1977 cm−1. This suggested an orientation in which the hydrogen was endo, and the carbonyl exo, to the macrocyclic cavity. Gold(I) and silver(I) complexes also form with the cations most likely adopting a trigonal planar C3v geometry, as shown in Figure 22, based on the symmetric 31P NMR

Synthesis of fluoranthenes by hydroarylation of alkynes catalyzed by gold(I) or gallium trichloride

• Sergio Pascual,
• Christophe Bour,
• Paula de Mendoza and
• Antonio M. Echavarren

Beilstein J. Org. Chem. 2011, 7, 1520–1525, doi:10.3762/bjoc.7.178

• /n, 43007 Tarragona, Spain 10.3762/bjoc.7.178 Abstract Electrophilic gold(I) catalyst 6 competes with GaCl3 as the catalyst of choice in the synthesis of fluoranthenes by intramolecular hydroarylation of alkynes. The potential of this catalyst for the preparation of polyarenes is illustrated by a

• synthesis of two functionalized decacyclenes in a one-pot transformation in which three C–C bonds are formed with high efficiency. Keywords: alkynes; gold(I) catalysis; hydroarylation; polyarenes; Introduction Electrophilic activation of alkynes in functionalized substrates by gold catalysts allows for

• large polyarenes 2 and more simple 3-arylfluoranthenes by using gold(I)- or gallium(III)-catalyzed hydroarylation reactions. Results and Discussion First, we examined the cyclization of 3 to give 4 or 4' [22][24][26] (Table 1) with cationic gold(I) catalysts 5 [56] and 6 [57] (Figure 1), which have been

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

• substrate was only 50% (Table 1, entry 7). Conversely, gold(I) species were unable to promote the cyclization of substrate 1b (Table 1, entries 8 and 9). In the presence of AuCl3, the ratio between the cyclization products 2b and 3b was significantly influenced by the solvent, as shown for the investigated

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

• explained either by direct fluorination of the enamine resulting from the gold-promoted alkyne hydroamination or by oxidation of the intermediate vinyl gold(I) complex by Selectfluor into a gold(III) fluoride species followed by a reductive elimination. Moreover, the formation of C(sp2)–F bonds, either by

• hydrofluorination of alkynes catalyzed by N-heterocyclic carbene gold(I) complexes [4], or by fluorodeauration of transient vinyl gold species [5][6], has been previously reported in the literature. On the basis of our recent results on the gold-catalyzed cyclization of enynes [7][8][9][10] and allenylhydrazones

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

• Michel Chiarucci Mirko Locritani Gianpiero Cera Marco Bandini Dipartimento di Chimica “G. Ciamician”, Alma Mater Studiorum – Università di Bologna, Via Selmi 2, 40126 Bologna, Italy 10.3762/bjoc.7.139 Abstract Gold(I)-N-heterocyclic carbene (NHC) complexes proved to be a reliable catalytic system

• . With the less bulky triphenylphosphine ligand, the corresponding cationic gold(I) complex (i.e., PPh3AuNTf2) led to an increase in the isolated yield up to 52%, although the diastereoselection remained elusive (≈ 1:1, entry 3). After demonstrating that the Au(III) catalysis promoted the cyclization in

Efficient gold(I)/silver(I)-cocatalyzed cascade intermolecular N-Michael addition/intramolecular hydroalkylation of unactivated alkenes with α-ketones

• Ya-Ping Xiao,
• Xin-Yuan Liu and
• Chi-Ming Che

Beilstein J. Org. Chem. 2011, 7, 1100–1107, doi:10.3762/bjoc.7.126

• Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China 10.3762/bjoc.7.126 Abstract The gold(I)/silver(I)-cocatalyzed cascade intermolecular N-Michael addition/intramolecular

• AgClO4 catalyzed intermolecular N-Michael addition and the subsequent gold(I)-catalyzed hydroalkylation is proposed. Keywords: cascade; cocatalyzed; gold(I)-catalyzed; intramolecular hydroalkylation; intermolecular N-Michael addition; pyrrolidine; silver(I)-catalyzed; Introduction Gold complexes are

• -cocatalysis see [39] and for Au/Rh-cocatalysis see [40]). However, the use of homogeneous gold catalysts in cooperation with other metal catalysts has been reported only in a few cases [30][31][32][33][34][35][36][37][38][39][40]. In this work, we describe a highly efficient gold(I)/silver(I)-cocatalyzed

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

• and reductive eliminations). Therefore, platinum(II) and particularly gold(I) or (III) complexes tend to activate alkynes, alkenes or allenes in a highly chemoselective manner; activation that opens interesting reaction pathways that usually involve carbocationic intermediates. Also very important is

• the possibility of modulating the properties of the metal through modification of its ancillary ligands (e.g., phosphines, N-heterocyclic carbenes, etc.), which considerably widens the potential and versatility of these catalysts, and in particular of those consisting of cationic gold(I) complexes

• (e.g., ligand–Au+). In this context, a number of research groups have in recent years embarked on the design and development of new cycloaddition reactions promoted by gold(I) and (III) catalysts, and hence the field has experienced a remarkable expansion. In the following section, we summarize some of

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

• 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

• improved thermal stability and substrate stability in the gold(I) promoted hydroamination and Hashmi phenol synthesis [42], which makes them interesting novel catalysts in the field of gold catalysis. One particular new development of the TA–Au catalysis that attracted our attention was the synthesis of α

• reactive functional group in gold catalysis, the substrate 4c was suitable for this transformation, giving the desired allene-ene 5c in excellent yield. Conclusion In this letter, we reported the application of triazole-coordinated gold(I) complexes as the effective catalysts for the promotion of the

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

• generate carbon-bridged frameworks of various sizes through a gold(I)-catalyzed carbocyclization [13]. Although the cyclization of enol ether 5 can produce 5-exo and 6-endo products, we found that gold complexes 6, having bulky phosphine ligands such as 2-bis(tert-butylphosphino)biphenyl, gave exclusively

• Diels–Alder reaction/Au(I)-catalyzed 6-endo-dig carbocyclization (Scheme 3). Cycloaddition between diene 12 and dienophile 13 should provide the endo cycloadduct 14, which, in the presence of a gold(I) catalyst, would form the gold complex A. This undergoes a carbocyclization of enol ether [24][25][26

• ) are underway and will be reported in due course. Structures of naturally occurring PPAPs. Gold(I)-catalyzed 6-endo-dig cyclization. Synthesis of papuaforin A core 4. Proposed domino Diels–Alder reaction/gold(I)-catalyzed cyclization. One-pot Diels–Alder cycloaddition/gold(I) catalyzed carbocyclization

Chiral gold(I) vs chiral silver complexes as catalysts for the enantioselective synthesis of the second generation GSK-hepatitis C virus inhibitor

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

Beilstein J. Org. Chem. 2011, 7, 988–996, doi:10.3762/bjoc.7.111

• gold(I) catalysts in this reaction was established by working with chiral phosphoramidites or with chiral BINAP. The best reaction conditions were used for the total synthesis of the hepatitis C virus inhibitor by a four step procedure affording this product in 99% ee and in 63% overall yield. The

• origin of the enantioselectivity of the chiral gold(I) catalyst was justified according to DFT calculations, the stabilizing coulombic interaction between the nitrogen atom of the thiazole moiety and one of the gold atoms being crucial. Keywords: BINAP; 1,3-dipolar cycloaddition; gold; HCV

• have been used for the synthesis of a similar key molecule 5b (R1 = t-Bu, 88% ee), but the overall synthesis of the antiviral drug was not reported [27][28]. In this article, we describe the full study concerning the enantioselective synthesis of product 5b using silver(I) or gold(I) complexes

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

• the zinc-catalyzed 7-exo-dig cyclization was reported specifically for a propargyl ether substrate [54]. Previously, we reported that semihollow-shaped triethylnylphosphine L1 (Figure 2) exerted marked acceleration effects in the gold(I)-catalyzed Conia-ene reactions of acetylenic keto esters and

• enyne cycloisomerizations. The new catalytic system has expanded the scope of the reactions to six- and seven-membered ring formations, which had been difficult with the conventional catalytic systems [55]. Furthermore, we found that L1–gold(I) complex efficiently catalyzed the cyclization of internal

• enhancement. Recently, we further developed the gold(I)-catalyzed 7-exo-dig cyclization of acetylenic silyl enol ethers with L1 [57]. In this context, we expected that the use of L1 as a ligand in the gold-catalyzed intramolecular hydroamination of alkynes would enable the construction of nitrogen-containing

Cationic gold(I) axially chiral biaryl bisphosphine complex-catalyzed atropselective synthesis of heterobiaryls

• Tetsuro Shibuya,
• Kyosuke Nakamura and
• Ken Tanaka

Beilstein J. Org. Chem. 2011, 7, 944–950, doi:10.3762/bjoc.7.105

• Tetsuro Shibuya Kyosuke Nakamura Ken Tanaka Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan 10.3762/bjoc.7.105 Abstract It has been established that a cationic gold(I)/(R)-DTBM-Segphos or (R)-BINAP

• hydroalkenylation and hydroarylation reactions [9][10][11][12][13][14][15]. In this context, our research group developed the cationic gold(I)/PPh3-complex catalyzed intramolecular hydroalkenylation of N-alkenyl-arylethynylamides leading to 4-aryl-2-pyridones (Scheme 1) [16][17]. The atropselective synthesis of 6

• from N-alkenyl-arylethynylamides was thus investigated. Although cationic gold(I)/axially chiral biaryl bisphosphine complexes [19][20][21][22][23][24][25][26][27][28][29][30][31] have been frequently employed in asymmetric variants of cationic gold(I) catalyses [32][33][34][35][36][37][38], including

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

• available heteroatom-substituted propargyl alcohols 10 has been developed by Aponick and co-workers [22]. For the formation of tetrahydropyran analogs 13 and 15, the gold(I)-catalyzed cyclization of monoallylic diols 12 and 14 is an efficient method (Scheme 2) [23][24]. In addition to common organic

• tetrahydropyran 24 were produced by an efficient gold(I) chloride catalyzed cycloisomerization of 2-alkynyl-1,5-diol 22 [28]. A plausible mechanism for the gold-catalyzed transformation of dioxabicyclo[4.2.1]ketal 25 to tetrahydropyran 31 is outlined in Scheme 5. The gold catalyst activates one of the oxygen

• atoms to form the intermediates 26 or 27, which then rearrange to yield the oxonium intermediates 28 or 29, respectively. Gold(I)-catalyzed intramolecular cyclization of monopropargylic triols 32 has been reported to be a novel and mild approach [29] for producing olefin-containing spiroketals 33 (and

The role of silver additives in gold-mediated C–H functionalisation

• Scott R. Patrick,
• Ine I. F. Boogaerts,
• Sylvain Gaillard,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2011, 7, 892–896, doi:10.3762/bjoc.7.102

• stoichiometric reaction between Ag2O and the substrate displayed substitution of one of the protons. However, deuterium incorporation experiments were unsuccessful and mass spectrometry on the product was inconclusive. The reaction depicted in Scheme 2 was performed using a neutral gold(I)-NHC complex. The

• suggests that complex 3 is indeed an intermediate. However, the use of a silver salt was essential for the reaction to proceed. The silver salt was suspected of abstracting the halide from [AuCl(IPr)] to generate a possibly active cationic gold(I) species [20]. To test this hypothesis, the well-defined

• cationic complex [(IPrAu+)(NCMe)][BF4-] [21] was reacted with 2 in the absence of other reagents. No product was observed. Subsequent test reactions were performed using 1 (Table 1, entries 1–3), thus eliminating the possible in situ formation of cationic gold(I). The reaction proved successful in the

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

• Florin M. Istrate Fabien Gagosz Département de Chimie, UMR 7652, CNRS/Ecole Polytechnique, 91128 Palaiseau, France 10.3762/bjoc.7.100 Abstract A series of ynenyl allyl ethers were rearranged into polysubstituted furans in the presence of a gold(I) catalyst. It is proposed that the transformation

• precursors for the formation of polysubstituted furans in the presence of a gold(I) or a gold(III) catalyst [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. We report herein our own investigations in this field which have led to the development

• (X = NTs) could be converted under mild experimental conditions into functionalized pyrroles 3 (X = NTs) in the presence of a gold(I) catalyst (Scheme 2) [52]. In contrast to Fürstners observations for the rearrangement of allyl pent-4-ynyl ethers [53][54], the results obtained during this study

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

• homopropargylic alcohol is protected as a MOM ether, a mixture of furans resulting from proto-demetallation 35 and MOM transfer 36 was obtained in a 75:25 ratio, respectively, whereas in the presence of gold(I) catalyst the proto-demetallation product 35 was the sole product. For related cyclization with

• an one-pot, sequential, reaction with first a gold(III)-catalyzed propargylic substitution followed by a gold(I)-catalyzed cycloisomerization, the bicyclic compound 37 was obtained in 71% yield [24][80][81][82]. Very recently, a remarkable one-pot reaction using an original gold(III) catalyst has

• impressive enantioselective intramolecular direct allylic substitutions using chiral gold(I) complexes [87][88]. We also took advantage of the π- and σ-(Lewis) acidities of gold(III) complexes to promote domino reactions with bi-nucleophiles such as protected hydroxylamines. In the presence of gold(III), the