N-Methylphthalimide-substituted benzimidazolium salts and PEPPSI Pd–NHC complexes: synthesis, characterization and catalytic activity in carbon–carbon bond-forming reactions

• Senem Akkoç,
• Yetkin Gök,
• İlhan Özer İlhan and
• Veysel Kayser

Beilstein J. Org. Chem. 2016, 12, 81–88, doi:10.3762/bjoc.12.9

• -iodoacetophenone as a substrate with phenylboronic acid (Table 2, entry 2). This catalytic system showed a better performance for aryl iodide than for aryl chlorides except chlorobenzene (Table 2, entries 1–17). 4-Acetylbiphenyl was obtained in 99% yield and 100% conversion at 80 °C and 1 h (Table 2, entry 2). The

Comparison of the catalytic activity for the Suzuki–Miyaura reaction of (η⁵-Cp)Pd(IPr)Cl with (η³-cinnamyl)Pd(IPr)(Cl) and (η³-1-t-Bu-indenyl)Pd(IPr)(Cl)

• Patrick R. Melvin,
• Nilay Hazari,
• Hannah M. C. Lant,
• Ian L. Peczak and
• Hemali P. Shah

Beilstein J. Org. Chem. 2015, 11, 2476–2486, doi:10.3762/bjoc.11.269

• preliminary reports indicate that (η5-Cp)Pd(NHC)(Cl) precatalysts are highly active. For example, full conversion at room temperature was achieved using simple aryl chlorides as the substrate in Suzuki–Miyaura couplings at relatively low catalyst loadings (1 mol %) [18]. However, despite this impressive

Half-sandwich nickel(II) complexes bearing 1,3-di(cycloalkyl)imidazol-2-ylidene ligands

• Johnathon Yau,
• Kaarel E. Hunt,
• Laura McDougall,
• Alan R. Kennedy and
• David J. Nelson

Beilstein J. Org. Chem. 2015, 11, 2171–2178, doi:10.3762/bjoc.11.235

• . The new species were fully characterised using methods including NMR spectroscopy and X-ray crystallography. When tested in model Suzuki–Miyaura cross-coupling reactions, these complexes were found to be active for the cross-coupling of aryl bromides and aryl chlorides. Keywords: catalysis; cross

• -coordination of the cyclopentadienyl ligand. Preliminary catalyst testing in model Suzuki–Miyaura reactions suggest that these more electron-donating ligands yield complexes that are slightly more active for the cross-coupling of aryl chlorides but less thermally stable. Further studies to fully explore and

Clean and fast cross-coupling of aryl halides in one-pot

• Valerica Pandarus,
• Geneviève Gingras,
• François Béland,
• Rosaria Ciriminna and
• Mario Pagliaro

Beilstein J. Org. Chem. 2014, 10, 897–901, doi:10.3762/bjoc.10.87

• emerging as a promising tool for synthetic organic chemistry [9]. In this research context, we have recently described the heterogeneously catalyzed synthesis of boronic acid pinacol esters using a wide range of aryl chlorides, bromides and iodides and bis(pinacolato)diboron as borylating agent over the

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• Pd-catalyzed aromatic trifluoromethylation of aryl chlorides with a nucleophilic source of CF3 has been reported in 2010 by S. L. Buchwald et al. (Table 2) [38]. An excess of expensive (trifluoromethyl)triethylsilane (TESCF3) in combination with potassium fluoride was used to provide the expected

• facilitate the reductive elimination step. However, the phosphine was changed for the less bulky ligand RuPhos for the reaction with ortho-substituted aryl chlorides. The authors presume a Pd(0)/Pd(II) catalytic cycle, which is supported by preliminary mechanistic studies. In 2011, B. S. Samant and G. W

Synthesis and structure of trans-bis(1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene)palladium(II) dichloride and diacetate. Suzuki–Miyaura coupling of polybromoarenes with high catalytic turnover efficiencies

• Jeelani Basha Shaik,
• Venkatachalam Ramkumar,
• Babu Varghese and
• Sethuraman Sankararaman

Beilstein J. Org. Chem. 2013, 9, 698–704, doi:10.3762/bjoc.9.79

• simple aryl chlorides. In this work we demonstrate that complex 1 is an excellent catalyst for multiple Suzuki–Miyaura coupling reactions of polybromoarenes. Reaction conditions were optimized using 1,4-dibromobenzene (6) and phenylboronic acid (5) as substrates. The reactions were carried out by using 2

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

• coupling partners. The desired coupling products were obtained in moderate to good yields by using 1 mol % of these air-stable palladium complexes. This is an advantage compared to the procedures employing air-sensitive phosphines, which have been previously shown to promote the coupling of aryl chlorides

• with heteroarenes. Keywords: aryl chlorides; atom-economy; C–H bond activation; C–H functionalization; carbenes; palladium; pyrroles; Introduction N-Heterocyclic carbenes (NHC) have emerged as an important class of ligands in the development of homogeneous catalysis [1][2][3][4][5][6][7][8][9]. Such

N-Heterocyclic carbene–palladium(II)-1-methylimidazole complex catalyzed Mizoroki–Heck reaction of aryl chlorides with styrenes

• Ting-Ting Gao,
• Ai-Ping Jin and
• Li-Xiong Shao

Beilstein J. Org. Chem. 2012, 8, 1916–1919, doi:10.3762/bjoc.8.222

• )-Im] complex 1 was found to be an effective catalyst for the Mizoroki–Heck reaction of a variety of aryl chlorides with styrenes. Both activated and deactivated aryl chlorides work well to give the corresponding coupling products in good to excellent yields by using tetrabutylammonium bromide (TBAB

• showed good catalytic activity toward activated aryl chlorides, are all lengthy [32][33][34][35][36]. Therefore, although the progress has been achieved for the NHC–Pd-complex-catalyzed Mizoroki–Heck reaction of aryl chlorides, the drive to develop easily available and widely applicable complexes with

• complex 1 was an active catalyst for the Mizoroki–Heck reaction of aryl chlorides, including both activated and deactivated aryl chlorides, with styrenes performed under air. Herein, we wish to report these results in detail. Results and Discussion Initially, the model reaction between chlorobenzene (2a

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

• achieve Pd(0)-catalyzed direct arylation of various electron-rich heterocycles, including benzoxazole with aryl chlorides (Scheme 12) [54]. Bhanage proposed the use of 2,2,6,6-tetramethyl-3,5-heptanedione ligand (TMHD) to achieve regioselective, Pd(0)-catalyzed, direct arylation of N-methylindole

• heterocycle series. Since the pioneering works of Ohta and Miura in the 1990s, the direct C–H substitutive coupling of (benz)oxazoles has been intensively studied under Pd(0)- and/or Cu(I)- and, more recently, Rh(I)- and Ni(0)- catalysis by using aryl (pseudo)halides, including less-expensive aryl chlorides

• trioxazoles [51]. Preparation of DPO- and POPOP-analogues [53]. Pd(0)-catalyzed direct arylation of benzoxazole with aryl chlorides [54]. Pd(0)-catalyzed direct C2-selective arylation of (benz)oxazoles with bromides and chlorides using bidentate ligands [55][56]. Palladium-catalyzed direct arylation of

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• coupling of aryl chlorides. This was followed by an intramolecular alkyne–hydroamination (addition of an N–H bond across a carbon–carbon multiple bond) leading to the corresponding indole derivatives 52. The amination/alkyne–hydroamination sequence requires the addition of 1.5 equiv of t-BuOK to reach

Functionalization of heterocyclic compounds using polyfunctional magnesium and zinc reagents

• Paul Knochel,
• Matthias A. Schade,
• Sebastian Bernhardt,
• Georg Manolikakes,
• Albrecht Metzger,
• Fabian M. Piller,
• Christoph J. Rohbogner and
• Marc Mosrin

Beilstein J. Org. Chem. 2011, 7, 1261–1277, doi:10.3762/bjoc.7.147

• problem only partially. It is expensive and most aryl or heteroaryl chlorides do not react. Therefore, we used a stronger reducing reagent, magnesium. Magnesium turnings readily insert into a variety of aryl chlorides or bromides in the presence of LiCl. However, arylmagnesium reagents are compatible with

Combined directed ortho-zincation and palladium-catalyzed strategies: Synthesis of 4,n-dimethoxy-substituted benzo[b]furans

• Verónica Guilarte,
• M. Pilar Castroviejo,
• Estela Álvarez and
• Roberto Sanz

Beilstein J. Org. Chem. 2011, 7, 1255–1260, doi:10.3762/bjoc.7.146

• aryl bromides instead of aryl chlorides. In addition, we also observed better yields for the corresponding benzofuran derivatives 9 (Table 3, entries 5–9) derived from the starting o-alkynylhalobenzene derivatives 6, bearing the two methoxy groups in a 3,5-relationship relative to the halide. Moreover

Air-stable, recyclable, and time-efficient diphenylphosphinite cellulose-supported palladium nanoparticles as a catalyst for Suzuki–Miyaura reactions

• Qingwei Du and
• Yiqun Li

Beilstein J. Org. Chem. 2011, 7, 378–385, doi:10.3762/bjoc.7.48

• reactivity of aryl bromides was slightly lower than that of the corresponding aryl iodides and in these cases a prolonged time was required. The reaction of aryl chlorides with arylboronic acids was sluggish and gave only small amounts of products in acceptable times. The reusability of the supported

Studies on Pd/NiFe₂O₄ catalyzed ligand-free Suzuki reaction in aqueous phase: synthesis of biaryls, terphenyls and polyaryls

• Sanjay R. Borhade and
• Suresh B. Waghmode

Beilstein J. Org. Chem. 2011, 7, 310–319, doi:10.3762/bjoc.7.41

• (Table 4, entry 35). Whereas, activated aryl chlorides gave the coupling product in moderate yields after 24 h (Table 4, entries 33, 34). Recently, terphenyls have attracted attention due to their wide range of significant biological applications including potent immunosuppressant, neuroprotective

Polyionic polymers – heterogeneous media for metal nanoparticles as catalyst in Suzuki–Miyaura and Heck–Mizoroki reactions under flow conditions

• Klaas Mennecke and
• Andreas Kirschning

Beilstein J. Org. Chem. 2009, 5, No. 21, doi:10.3762/bjoc.5.21

• excellent. Aryl chlorides did not react with catalyst 3 under flow conditions. To fully explore the potential of polyionic gel 3 its reusability was investigated next. The Suzuki reaction of 4-bromotoluene (6) with phenylboronic acid (10) served as model reaction. After each reaction the continuous flow

• ] these clusters exert pronounced catalytic activity in solution at very low concentrations. This view is further supported by the fact that the catalytic species operating in the present case is able to promote Suzuki–Miyaura cross coupling reactions with aryl bromides while aryl chlorides are not good

• high pressure/high temperature conditions aryl chlorides (for Suzuki–Miyaura reactions) or aryl bromides (for Heck–Mizoroki reactions) may very well serve as substrates for this kind of palladium species. Conclusion In summary, we demonstrated that polyionic gel 3 is a well suited ion exchange resin

Synthesis of dihydrophenanthridines by a sequence of Ugi-4CR and palladium- catalyzed intramolecular C-H functionalization

• Florence Bonnaterre,
• Michèle Bois-Choussy and
• Jieping Zhu

Beilstein J. Org. Chem. 2008, 4, No. 10, doi:10.3762/bjoc.4.10

• functionalization taking advantage of transition metal catalyzed transformation of aryl chlorides [36]. When Ugi adducts 6j and 6k (entries 10, 11) were subjected to the CH-arylation procedure, two regioisomers were produced. Interestingly, in the case of 6k, a sterically more hindered isomer (1k-b) was produced

A convenient catalyst system for microwave accelerated cross- coupling of a range of aryl boronic acids with aryl chlorides

• Matthew L. Clarke,
• Marcia B. France,
• Jose A. Fuentes,
• Edward J. Milton and
• Geoffrey J. Roff

Beilstein J. Org. Chem. 2007, 3, No. 18, doi:10.1186/1860-5397-3-18

• microwave accelerated cross-coupling procedure between aryl chlorides with a range of boronic acids has been developed. An explanation for the low reactivity of highly fluorinated boronic acids in Suzuki coupling is provided. Background The Suzuki cross-coupling represents an extremely useful method for

• ligand, dcpmp, 1 gave very active catalysts for this reaction[13]. At the time this system was one of the few catalysts capable of cross-coupling unactivated aryl chlorides below 100°C. Reaction times were typically 12 hours or slightly less. More recently, advances in chemical microwave technology have

• small number of these catalyst systems have been found to deliver microwave accelerated aryl chloride cross-coupling, and in the course of another project, we discovered that the Pd/dcpmp catalyst system was just such a catalyst. [27] This has led us to investigate cross-coupling of aryl chlorides with