Exploration of C–H and N–H-bond functionalization towards 1-(1,2-diarylindol-3-yl)tetrahydroisoquinolines

• Michael Ghobrial,
• Marko D. Mihovilovic and
• Michael Schnürch

Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226

• well established via a series of transformations. The direct arylation via C–H functionalization represents a very efficient approach in this regard [24][25][26][27][28][29][30][31] with methods available to either decorate position 2 or 3 regioselectively [32][33][34][35][36][37][38][39][40][41][42

Synthesis of trifluoromethyl-substituted pyrazolo[4,3-c]pyridines – sequential versus multicomponent reaction approach

• Barbara Palka,
• Angela Di Capua,
• Maurizio Anzini,
• Gyté Vilkauskaité,
• Algirdas Šačkus and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2014, 10, 1759–1764, doi:10.3762/bjoc.10.183

• multicomponent reaction following the path 2→9→7. Azine N-oxides of type 7 are estimated to be of particular interest due to the possibility of further functionalization adjacent to the nitrogen atom (position 4), for instance by palladium-catalyzed direct arylation reactions [31]. NMR spectroscopic

Hindered aryl bromides for regioselective palladium-catalysed direct arylation at less favourable C5-carbon of 3-substituted thiophenes

• Rongwei Jin,
• Charles Beromeo Bheeter and
• Henri Doucet

Beilstein J. Org. Chem. 2014, 10, 1239–1245, doi:10.3762/bjoc.10.123

• variety of arylated thiophenes. For such coupling reactions, the major byproduct is a base associated to HX, instead of metallic salts which are produced under the more classical Negishi, Suzuki or Stille cross-coupling reactions. Moreover, direct arylation avoids the preliminary preparation of

• to selectively arylate positions C2 or C5. The direct arylation of 3-methoxythiophene, which was studied by Borghese and co-workers afforded regioselectively the C2-arylated thiophenes in moderate to high yields [28]. Finally, in the course of their studies on sp3 C–H bond activation, Baudoin and

• slightly more reactive than position C5), the control of the regioselectivity of the palladium-catalysed direct arylation of such thiophene derivatives especially to provide 5-arylthiophenes remains a challenging reaction. Our goal was to promote arylation at carbon C5 of a range of 3-substituted

4-Hydroxy-6-alkyl-2-pyrones as nucleophilic coupling partners in Mitsunobu reactions and oxa-Michael additions

• Michael J. Burns,
• Thomas O. Ronson,
• Richard J. K. Taylor and
• Ian J. S. Fairlamb

Beilstein J. Org. Chem. 2014, 10, 1159–1165, doi:10.3762/bjoc.10.116

• could find only limited precedent for this procedure being used previously in this way [15][16][17]. In our case, we were able to further modify the resulting pyronyl ether forming a trisubstituted enol ether, which then underwent a Suzuki–Miyaura cross-coupling or direct arylation-type reaction. As

An easy direct arylation of 5-pyrazolones

• Hao Gong,
• Yiwen Yang,
• Zechao Wang and
• Chunxiang Kuang

Beilstein J. Org. Chem. 2013, 9, 2033–2039, doi:10.3762/bjoc.9.240

• Education, Shanghai 200092, China 10.3762/bjoc.9.240 Abstract A mild, efficient and catalytic ligand-free method for the direct arylation of 5-pyrazolones by Pd-catalyzed C–H bond activation is reported. The process smoothly proceeds and yields are moderate to excellent. Keywords: arylation; aryl halide

• synthesize a new series of heterocyclic compounds containing the pyrazolone moiety. The reaction of pyrazolones with arylboronic acids is an attractive approach for the synthesis of arylpyrazolone [15][16]. However, it often needs pre-formation of halo-pyrazolones. Transition metal-catalyzed direct arylation

• of (hetero)arenes has emerged over the past few years as a rapidly growing field of syntheses [17][18][19][20][21][22][23][24][25][26]. The direct arylation of pyrazolones by using aryl halides offers a cleaner and more efficient method of meeting such goals and rare examples of such transformations

AgOTf-catalyzed one-pot reactions of 2-alkynylbenzaldoximes with α,β-unsaturated carbonyl compounds

• Qiuping Ding,
• Dan Wang,
• Puying Luo,
• Meiling Liu,
• Shouzhi Pu and
• Liyun Zhou

Beilstein J. Org. Chem. 2013, 9, 1949–1956, doi:10.3762/bjoc.9.231

• /Pd-catalyzed direct arylation of 2-alkynylbenzaldoximes [41]. Inspired by the key contributions from the groups of Wu [36][37][38][39] and Deng [40], we envisioned that 1-alkylated isoquinolines could be generated in a one-pot AgOTf-catalyzed cyclization/1,3-dipolar cycloaddition/rearrangement or

Enantioselective synthesis of planar chiral ferrocenes via palladium-catalyzed annulation with diarylethynes

• Yan-Chao Shi,
• Rong-Fei Yang,
• De-Wei Gao and
• Shu-Li You

Beilstein J. Org. Chem. 2013, 9, 1891–1896, doi:10.3762/bjoc.9.222

• ][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. Inspired by their works, we reported a direct arylation of ferrrocene with arylboronic acid to introduce planar chirality into the ferrocene backbone using N,N-dimethylaminomethyl as the directing group and Boc-L-Val-OH as the ligand

Palladium-catalyzed synthesis of N-arylated carbazoles using anilines and cyclic diaryliodonium salts

• Stefan Riedmüller and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2013, 9, 1202–1209, doi:10.3762/bjoc.9.136

• ] or the direct arylation [14][15] of the free NH-functionality of carbazole (path B). In the past decade, hypervalent iodine chemistry has undergone a renaissance and has developed to become a powerful area in synthetic organic chemistry. Open-chained iodonium salts are well explored in transition

N-Heterocyclic carbene–palladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides

• Ismail Özdemir,
• Nevin Gürbüz,
• Nazan Kaloğlu,
• Öznur Doğan,
• Murat Kaloğlu,
• Christian Bruneau and
• Henri Doucet

Beilstein J. Org. Chem. 2013, 9, 303–312, doi:10.3762/bjoc.9.35

• Catalysis", Campus de Beaulieu, 35042 Rennes, France. Fax: +33 (0)2-23-23-69-39; Tel: +33 (0)2-23-23-63-84 10.3762/bjoc.9.35 Abstract New Pd–NHC complexes have been synthesized and employed for palladium-catalyzed direct arylation of pyrrole derivatives by using electron-deficient aryl chlorides as

• palladium-catalyzed direct arylation of various heteroaromatics including pyrroles by a C–H bond activation using aryl halides has met great success in recent years, allowing the synthesis of a wide variety of arylated heteroaromatics in only one step [20][21][22][23][24][25]. However, there are still

• imidazolylidene carbene ligands for the Pd-catalyzed direct arylation of pyrroles or indoles using bromobenzene and aryl iodides [42]. They observed that an important steric demand on the carbene ligand led to better results. Recently, the use of palladium(II) acetate complexes bearing both a phosphine and a

Copper-catalyzed CuAAC/intramolecular C–H arylation sequence: Synthesis of annulated 1,2,3-triazoles

• Rajkumar Jeyachandran,
• Harish Kumar Potukuchi and
• Lutz Ackermann

Beilstein J. Org. Chem. 2012, 8, 1771–1777, doi:10.3762/bjoc.8.202

• efficiently with LiOt-Bu as the stoichiometric base, K3PO4 only led to unsatisfactory results, even when additional stabilizing ligands were used (Table 1, entries 7–10). With optimized reaction conditions for the intramolecular direct arylation in hand, we tested the possibility of its implementation in a

• - and step-economical access to annulated carbo- as well as O- and N-heterocycles. Finally, we found that the catalytic system also proved to be applicable to the one-pot copper-catalyzed direct arylation of various azoles 5 through N–H/C–H bond cleavages with aryl iodides 6 as the organic electrophiles

• of isolated product. Copper-catalyzed one-pot twofold C–H/N–H arylation with azoles 5. aReaction performed at 120 °C. Optimization studies for the intramolecular direct arylation of triazole 3a.a Supporting Information Supporting Information containing all experimental details and analytical data of

Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes

• Gianluigi Broggini,
• Egle M. Beccalli,
• Andrea Fasana and
• Silvia Gazzola

Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198

• the reactivity of some Ar-Pd(II) complexes with arenes (through a proton-transfer palladation mechanism), depending on the C–H acidity rather than the arene nucleophilicity. Synthetic procedures based on this strategy allowed the direct arylation at C-2 and C-3 positions of indoles 9 with a high

Extending the utility of [Pd(NHC)(cinnamyl)Cl] precatalysts: Direct arylation of heterocycles

• Anthony R. Martin,
• Anthony Chartoire,
• Alexandra M. Z. Slawin and
• Steven P. Nolan

Beilstein J. Org. Chem. 2012, 8, 1637–1643, doi:10.3762/bjoc.8.187

• Anthony R. Martin Anthony Chartoire Alexandra M. Z. Slawin Steven P. Nolan EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, UK 10.3762/bjoc.8.187 Abstract The use of [Pd(NHC)(cinnamyl)Cl] precatalysts in the direct arylation of heterocycles has been

• . Keywords: C–H functionalization; direct arylation; heterocycles; N-heterocyclic carbenes; palladium; Introduction As a powerful addition to the classic palladium cross-coupling reactions, C–H bond functionalization has become a growing field of research over the last few years. The ubiquity of C–H bonds

• efficiency of well-defined palladium catalysts bearing NHC (N-heterocyclic carbene) ancillary ligands in classical cross-coupling reactions, they have rarely been applied to direct arylation procedures [9][10][11][12][13][14][15][16]. Among the family of [Pd(NHC)] complexes, the [Pd(NHC)(cin)Cl] (cin

Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

• Jiří Kulhánek and
• Filip Bureš

Beilstein J. Org. Chem. 2012, 8, 25–49, doi:10.3762/bjoc.8.4

• –111 (Figure 19; [20]). In contrast to a typical synthetic approach to diimidazoles as shown in Scheme 1, we used 4,5-dicyanoimidazole derivatives 1–3 (Scheme 2) and modern direct arylation, Suzuki–Miyaura, Sonogashira, and Heck reactions to construct molecules 101–111. These chromophores possess two

Recent advances in direct C–H arylation: Methodology, selectivity and mechanism in oxazole series

• Cécile Verrier,
• Pierrik Lassalas,
• Laure Théveau,
• Guy Quéguiner,
• François Trécourt,
• Francis Marsais and
• Christophe Hoarau

Beilstein J. Org. Chem. 2011, 7, 1584–1601, doi:10.3762/bjoc.7.187

• in this article. Methodologies, selectivity, mechanism and future aspects are presented. Keywords: ate complex; catalytic direct arylation; mechanism; oxazole; selectivity; transition-metal catalysis; Introduction Deprotonative metalation of aromatics is widely used as a powerful method for

• ]. Over the past decade, alternatives for more expeditive, practical and chemoselective arylating technics have arisen, thanks mainly to the great development of novel, stoichiometric and catalytic, direct arylation methodologies (Scheme 1). Thus novel classes of metallating agents resulting from various

• electrophilic reactions as well as transition-metal-catalyzed cross-coupling reactions. By contrast, the methodology for transition-metal-catalyzed direct arylation [13][14][15][16][17][18] is based upon the use of various catalytic metalation processes, such as electrophilic metalation, oxidative addition