Gold(I)-catalyzed hydroarylation reaction of aryl (3-iodoprop-2-yn-1-yl) ethers: synthesis of 3-iodo-2H-chromene derivatives

• Pablo Morán-Poladura,
• Eduardo Rubio and
• José M. González

Beilstein J. Org. Chem. 2013, 9, 2120–2128, doi:10.3762/bjoc.9.249

• competition with a direct Friedel–Crafts-type cyclization reaction yielding 3. In previous work dealing with the cyclization of N-(3-iodoprop-2-ynyl)-N-tosylanilines to give related 1,2-dihydroquinolines (Scheme 4A, X = NTs) [43], we documented for a phosphite-based gold-catalyst, which render a more

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• ]. The synthesis commenced with the preparation of the isoindolinone building block 134. Friedel–Crafts acetylation of 132, followed by a Lieben haloform degradation gave the corresponding acid, which after methylation yielded 133. Bromination and lactam formation afforded isoindolinone 134. The

• oxalyl chloride and the Lewis acid tin(IV) chloride, a tandem cyclization (Bischler–Napieralski/Friedel–Crafts acylation reaction) was triggered to directly give 137 and 149 [122][127]. In 2006, another approach to aristoyagonine (136) was reported by the group of Couture (Scheme 20) [128]. For the

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

• allylation/intramolecular hydroalkoxylation sequence. The reaction is mild, practical and tolerant of a wide variety of substituents on the phenol. Keywords: allylic alcohols; chromans; Friedel–Crafts; gold catalysis; heterocycles; Introduction Chromans (dihydrobenzopyrans) are important and ubiquitous

• structural motifs found in a variety of important biologically active natural products such as vitamin E and flavanoids [1][2][3][4][5]. One approach towards chromans [6][7][8][9][10][11][12], which is biosynthetically inspired, is the Friedel–Crafts allylation [13] of phenols followed by cyclisation of the

Catalytic asymmetric tandem Friedel–Crafts alkylation/Michael addition reaction for the synthesis of highly functionalized chromans

• Jiahuan Peng and
• Da-Ming Du

Beilstein J. Org. Chem. 2013, 9, 1210–1216, doi:10.3762/bjoc.9.137

• Jiahuan Peng Da-Ming Du School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, China 10.3762/bjoc.9.137 Abstract The enantioselective tandem Friedel–Crafts alkylation/Michael addition reaction of indoles with nitroolefin enoates catalyzed by a

• diphenylamine-linked bis(oxazoline)-Zn(OTf)2 complex was investigated. This tandem reaction afforded functionalized chiral chromans in good yields with moderate to high stereoselectivities (up to 95:5 dr, up to 99% ee). Keywords: asymmetric catalysis; bis(oxazoline); chroman; Friedel–Crafts alkylation; tandem

• [21][22][23][24][25][26][27][28][29][30][31][32]. Chiral indolyl(nitro)chromans have been successfully synthesized in our previous study [33]. Good results were obtained in the diastereo- and enantioselective Friedel–Crafts alkylation of indoles with 3-nitro-2H-chromenes catalyzed by diphenylamine

Camera-enabled techniques for organic synthesis

• Steven V. Ley,
• Richard J. Ingham,
• Matthew O’Brien and
• Duncan L. Browne

Beilstein J. Org. Chem. 2013, 9, 1051–1072, doi:10.3762/bjoc.9.118

• product within the microdroplets to be visualised accurately (Figure 6). Another beneficial way to use a camera to assist in a reaction optimisation is simply to see what is happening in an otherwise inaccessible reaction vessel or closed cavity. During studies on the Friedel–Crafts alkylation of anisole

• setup that might not otherwise be available. Suzuki–Miyaura reaction performed within a microfluidic system. The product is observed by high-speed microscope photography, which shows a precipitate forming within the microdroplets. Friedel–Crafts reactions performed by using solid-acid catalysis at high

A versatile and efficient approach for the synthesis of chiral 1,3-nitroamines and 1,3-diamines via conjugate addition to new (S,E)-γ-aminated nitroalkenes derived from L-α-amino acids

• Vera Lúcia Patrocinio Pereira,
• André Luiz da Silva Moura,
• Daniel Pais Pires Vieira,
• Leandro Lara de Carvalho,
• Eliz Regina Bueno Torres and
• Jeronimo da Silva Costa

Beilstein J. Org. Chem. 2013, 9, 832–837, doi:10.3762/bjoc.9.95

• nucleophiles [5][6][7][8][9][10], in Friedel–Crafts alkylations [11][12][13][14], and Baylis–Hillman reactions [15][16][17][18]. Furthermore, nitroalkenes can react as dipolarophiles in [3 + 2] cycloadditions [19][20][21][22], as dienophiles in [4 + 2] cycloadditions [23][24][25][26], and as heterodienes in

Some aspects of radical chemistry in the assembly of complex molecular architectures

• Béatrice Quiclet-Sire and
• Samir Z. Zard

Beilstein J. Org. Chem. 2013, 9, 557–576, doi:10.3762/bjoc.9.61

• –cyclisation leading to indoline 97 with an intramolecular Friedel–Crafts reaction to afford a tricyclic derivative 98 substituted by a trifluoromethyl group [44]. The second exploits the presence of both a protected primary amine and an easily substitutable chlorine on the pyrimidine ring in 99a,b to afford

• , which smoothly undergoes an intramolecular Friedel–Crafts reaction to generate the last ring in intermediate 169. Finally, reduction of the lactam and unmasking of the ketone causes the migration of the olefin to complete the synthesis of the target structure 170. The generation of radicals using nickel

Polymerization of novel methacrylated anthraquinone dyes

• Christian Dollendorf,
• Susanne Katharina Kreth,
• Soo Whan Choi and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 453–459, doi:10.3762/bjoc.9.48

• absorption in two different areas of the visible spectrum. Polymerizable blue dye 6 based on anthraquinone For the synthesis of the blue anthraquinone based monomeric dye 6, the precursor 1,4-dichloroanthraquinone (3) was prepared by the reaction of 1,4-dichlorobenzene with phthalic dichloride by Friedel

• –Crafts acylation followed by an acidic ring closure (Scheme 1, step b). In further reaction steps, 1,4-dichloroanthraquinone (3) and hydroxyaniline were reacted to obtain 1,4-bis(4-hydroxyphenylamino)anthraquinone (4). Subsequent reaction with 2-bromoethanol gave 1,4-bis(4-((2-hydroxyethyl)oxy

Iron-containing mesoporous aluminosilicate catalyzed direct alkenylation of phenols: Facile synthesis of 1,1-diarylalkenes

• Satyajit Haldar and
• Subratanath Koner

Beilstein J. Org. Chem. 2013, 9, 49–55, doi:10.3762/bjoc.9.6

• reagents to afford 1,1-disubstituted olefins [27]. Alternatively, Friedel–Crafts-type alkenylation could be a better choice to prepare such regiospecific vinyl aromatic compounds. Yamaguchi et al. reported a direct ortho alkenylation of phenols with 1-alkynes using SnCl4 and Bu3N in acetonitrile under

• reflux [28]. Further developments include the metal trifluoromethanesulfonate-catalyzed Friedel–Crafts alkenylation of arenes using alkynes by Tsuchimoto et al. [29] and the addition of simple arenes to arylacetylenes to afford exclusive 1,1-diarylethylenes through a C–C coupling reaction catalyzed by a

• (III) chloride [32]. Nevertheless, all of these Lewis acid catalyzed Friedel–Crafts-type reactions have their own limitations. Being homogeneous catalytic systems, these methods suffer from drawbacks, such as difficulty in recovery and reusability of the catalysts and tedious work-up procedures. In

An efficient access to the synthesis of novel 12-phenylbenzo[6,7]oxepino[3,4-b]quinolin-13(6H)-one derivatives

• Wentao Gao,
• Guihai Lin,
• Yang Li,
• Xiyue Tao,
• Rui Liu and
• Lianjie Sun

Beilstein J. Org. Chem. 2012, 8, 1849–1857, doi:10.3762/bjoc.8.213

• , is described, involving the intramolecular Friedel–Crafts acylation reaction of 2-(phenoxymethyl)-4-phenylquinoline-3-carboxylic acid derivatives 3a–l aided by the treatment with PPA (polyphosphoric acid) or Eaton’s reagent. The required starting compound (2) was obtained by Friedländer reaction of 2

• three-step route, offers easy access to tetracyclic-fused quinoline systems in short reaction times, and the products are obtained in moderate to good yields. Keywords: Eaton’s reagent; Friedel–Crafts acylation; Friedländer reaction; one-pot; PPA; quinoline; tetracyclic-fused; Introduction Polycyclic

• nature of the bulky tert-butyl group at the o-position of aryl. Thus, the resulting substrates, quinoline-3-carboxylic acids 3a–l, further served as active synthons for the intramolecular Friedel–Crafts acylation reaction to construct the desired tetracyclic benzoxepino-fused quinoline systems. Of the

C2-Alkylation of N-pyrimidylindole with vinylsilane via cobalt-catalyzed C–H bond activation

• Zhenhua Ding and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2012, 8, 1536–1542, doi:10.3762/bjoc.8.174

• different when it comes to direct C–H alkylation [10][11]. The intrinsically nucleophilic C3 position of indole is amenable to a variety of catalytic alkylation reactions such as Friedel–Crafts reaction [5]. On the other hand, C2-alkylation of indoles has traditionally required 2-lithioindoles generated by

Asymmetric one-pot sequential Friedel–Crafts-type alkylation and α-oxyamination catalyzed by a peptide and an enzyme

• Kengo Akagawa,
• Ryota Umezawa and
• Kazuaki Kudo

Beilstein J. Org. Chem. 2012, 8, 1333–1337, doi:10.3762/bjoc.8.152

• -functionalized indole or pyrrole derivatives in a highly enantioselective manner. Keywords: Friedel–Crafts-type alkylation; laccase; one-pot reaction; organocatalysis; α-oxyamination; resin-supported peptide catalyst; Findings Indole derivatives represent a class of biologically active compounds [1][2][3], and

• they often have chiral carbon chains attached to indole rings. A Friedel–Crafts-type asymmetric alkylation (FCAA) to indoles is a versatile method for synthesizing such chiral indole derivatives. To date, a number of FCAA reactions by either metal catalysts or organocatalysts have been reported [4][5

• -pot sequential Friedel–Crafts-type alkylation/α-oxyamination. Examples of the one-pot synthesis of oxygenated heteroaromatic compounds. Supporting Information Supporting Information File 340: Typical experimental procedure, spectroscopic data for products, determination of stereochemistry, 1H and 13C

Diarylethene-modified nucleotides for switching optical properties in DNA

• Sebastian Barrois and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2012, 8, 905–914, doi:10.3762/bjoc.8.103

• yield. The resulting 5-bromo-2-methylbenzothiazole (8) was converted in a double Friedel–Crafts-type acylation. Treatment with glutaryl chloride in the presence of AlCl3 connects two benzothiazoles 8 and provides 9 in 74% yield. The double McMurry-type reaction, which is performed with Zn and TiCl4

Ion-exchange-resin-catalyzed adamantylation of phenol derivatives with adamantanols: Developing a clean process for synthesis of 2-(1-adamantyl)-4-bromophenol, a key intermediate of adapalene

• Nan Wang,
• Ronghua Wang,
• Xia Shi and
• Gang Zou

Beilstein J. Org. Chem. 2012, 8, 227–233, doi:10.3762/bjoc.8.23

• derivatives are the key skeletons of synthetic retinoid analogues [1][2][3][4][5][6][7][8][9] and supporting ligands of many homogeneous transition-metal catalysts [10][11][12][13][14]. Introduction of an adamantyl group to the phenol ring has largely relied on acid-catalyzed Friedel–Crafts alkylation with

• catalyze adamantylation of aromatics with 1-bromoadamantane similarly to organic sulfonic acids or their fluorinated analogues. However, due to the detrimental effects of water on the catalytic activity of the cation-exchange resin in Friedel–Crafts alkylation, there is, to the best of our knowledge, no

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

• complementarity between the arrangement of phenolic groups and the preferred coordination environment of Na+. Removal of the tert-butyl groups through a conventional AlCl3 driven retro-Friedel–Crafts de-tert-butylation reaction, as seen in other calixarenes, is unsuccessful in the case of oxacalixarenes

• -substituted phenol; however, in host–guest chemistry an asymmetric macrocycle can provide a site for enantioselective molecular recognition. In the case of p-tert-butylcalix[n]arenes the tert-butyl substituent can be removed, as mentioned previously, through a retro-Friedel–Crafts acylation, and replaced by

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

• the synthesis of complex molecules under mild conditions [1][2][3][4][5][6][7][8]. Alkynes can react in gold-catalyzed Friedel–Crafts-type reactions with arenes to give products resulting from the intermolecular hydroarylation of the alkynes (or alkenylation of the arenes) [9][10][11][12][13][14][15

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

• vinylbutyrolactones [18][19][20][21][22] as minor products in the Friedel–Crafts-type allylic alkylation of arenes [23]. The wide impact of functionalized γ-lactones on the synthesis of naturally occurring compounds [24][25][26] prompted us to optimize a direct synthesis of vinylbutyrolactones by direct gold

• were tested and a direct comparison of performances can be made. Clear evidence was gained for the higher activity of the catalytic system A in the expected oxaallylic alkylation process. As an example, when multiple reactive channels were available (i.e., lactonization and Friedel–Crafts-type

One-pot four-component synthesis of pyrimidyl and pyrazolyl substituted azulenes by glyoxylation–decarbonylative alkynylation–cyclocondensation sequences

• Charlotte F. Gers,
• Julia Rosellen,
• Eugen Merkul and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1173–1181, doi:10.3762/bjoc.7.136

• , such as Friedel–Crafts-type reactions, generally occurs in the 1-position [24]. Interestingly, the azulene motif is also found in terpenoids [27][28]. Guaiazulene (1b) (Scheme 1), a commonly known derivative of azulene (1a), is a naturally occurring sesquiterpene [29]. Guaiazulene (1b) has found entry

A practical microreactor for electrochemistry in flow

• Kevin Watts,
• William Gattrell and
• Thomas Wirth

Beilstein J. Org. Chem. 2011, 7, 1108–1114, doi:10.3762/bjoc.7.127

• be used in different subsequent reactions (Scheme 1). The first reaction studied was a Friedel–Crafts reaction of aromatic compounds. In comparison with the "cation pool" method, the "cation flow" method was far more successful for this reaction, producing the monoalkylated product 2 in 92% yield in

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

• Friedel–Crafts-type cyclization, which completes the catalytic cycle and regenerates the gold catalyst [39][60]. Interestingly, small changes in the substitution of the alkene, or the use of other catalysts, such as PtCl2 (under a CO atmosphere), affect the result of the annulation, such that it is now

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

• process [35]. As shown in Scheme 2b, with the [IPr–Au]+ catalyst, only trace amount of the allene 2a was obtained. The major product derived from the Friedel–Crafts addition of the aromatic ring to the gold activated allene. Therefore, selective activation of the alkyne over the allene was considered as a

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

• -piperidine derivatives. Some functionalized carbo- and heterocycles 232 were synthesized via gold-catalyzed cycloisomerization reactions of enynes 231 [110]. The PPh3AuCl/AgSbF6 catalytic system promotes a Friedel–Crafts type addition of electron-rich aromatic and heteroaromatic derivatives to the non

• Friedel–Crafts/furan–yne cyclization/heteroenyne metathesis was developed for the highly efficient construction of phenanthrene derivatives 270 [144]. Both AuCl3 and PPh3AuCl are effective catalysts for all the processes in the reaction and a variety of diyne substrates 271 could be used (Scheme 48

• ). Similar strategies [145][146] were applied to synthesize arylated (Z)-enones, -enals or dihydrocyclohepta[b]indole skeletons 277 by gold-catalyzed cascade Friedel–Crafts/furan (or indole)–alkyne cycloisomerizations (Scheme 48). The polysubstituted butenolides 281 could be obtained through a gold-catalyzed

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

• Friedel–Crafts type reactions with benzylic and propargylic alcohols. Shortly after, Sanz and Zhan discovered, that these reactions could also be carried out under Brønsted acid and FeCl3 catalysis, respectively [26][27][28][29]. Later, the use of copper, indium, bismuth, scandium, ytterbium

Homoallylic amines by reductive inter- and intramolecular coupling of allenes and nitriles

• Peter Wipf and
• Marija D. Manojlovic

Beilstein J. Org. Chem. 2011, 7, 824–830, doi:10.3762/bjoc.7.94

• , the utility of the hydrozirconation of nitriles can be enhanced by using Lewis acids to engage nitrile-derived acylimines in Friedel–Crafts reactions, generating indanyl or tetrahydronaphthyl derivatives [34][35]. Previous work in our group had concentrated on the transmetalation of alkenyl- and

Synthetic applications of gold-catalyzed ring expansions

• David Garayalde and
• Cristina Nevado

Beilstein J. Org. Chem. 2011, 7, 767–780, doi:10.3762/bjoc.7.87

• activation of the cyclopropene, cation 55 is formed. C–C bond cleavage of the cyclopropyl ring followed by a Friedel–Crafts reaction affords, after recovery of aromaticity, the observed products [47]. 4 Ring expansions involving annulation reactions Diels–Alder, [1,3]-dipolar-, [2 + 2]- and [4 + 3