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

• direct (hetero)arylation of (hetero)arenes is an attractive alternative to traditional Kumada, Stille, Negishi and Suzuki–Miyaura cross-coupling reactions, notably as it avoids the prior preparation and isolation of (hetero)arylmetals. Developments of this methodology in the oxazole series are reviewed

• , aminomethylation, sulfuration, oxygenation). However, aryllithiums can rarely be directly involved in transition-metal-catalyzed cross-coupling reactions and are usually transformed into organometallic fragments suitable for efficient Negishi, Stille, Suzuki–Miyaura, and Hiyama cross-coupling reactions [1][2

A novel and facile synthesis of 3-(2-benzofuroyl)- and 3,6-bis(2-benzofuroyl)carbazole derivatives

• Wentao Gao,
• Meiru Zheng and
• Yang Li

Beilstein J. Org. Chem. 2011, 7, 1533–1540, doi:10.3762/bjoc.7.180

• presence of fluorine, chlorine, or bromine substituents (entries 6–11) is not problematic, thereby providing a potential handle for further functionalization (eg., Heck and Suzuki–Miyaura reactions) of the corresponding products 3f–k. In the cases of entries 9–11, the tert-butyl-substituted products 3i–k

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

• stereoselectivity. A four-component reaction was further developed through an in situ post C–B arylation by adding a second aryl iodide, with Cs2CO3 and water, to the newly formed alkenylboronate 78. The subsequent Suzuki–Miyaura coupling led to the formation of 2,3-diarylated amines 79 and the best results were

Bromine–lithium exchange: An efficient tool in the modular construction of biaryl ligands

• Laurence Bonnafoux,
• Frédéric R. Leroux and
• Françoise Colobert

Beilstein J. Org. Chem. 2011, 7, 1278–1287, doi:10.3762/bjoc.7.148

• -methylation with iodomethane in acetone. 2,2'-Dibromo-6-methoxybiphenyl (1d) was finally obtained in a very good global yield of 68% in 3 steps. Finally, we proposed to introduce the phenyl ring (1f, 95%) by a regioselective Suzuki–Miyaura coupling via the iodo derivative 1e, the latter being obtained in 83

Directed aromatic functionalization

• Victor Snieckus

Beilstein J. Org. Chem. 2011, 7, 1215–1218, doi:10.3762/bjoc.7.141

• insertion, the gates of the synthetic arena were spectacularly opened to the 2010 Nobel Prize chemistry and the general theme of transition metal-catalyzed reactions. Thus, the named reactions of Kumada–Corriu, Negishi, Suzuki–Miyaura, Stille and, most recently, Hiyama have all given new insights into how

Scaling up of continuous-flow, microwave-assisted, organic reactions by varying the size of Pd-functionalized catalytic monoliths

• Ping He,
• Stephen J. Haswell,
• Paul D. I. Fletcher,
• Stephen M. Kelly and
• Andrew Mansfield

Beilstein J. Org. Chem. 2011, 7, 1150–1157, doi:10.3762/bjoc.7.133

• been developed to perform Suzuki–Miyaura reactions under a microwave heating regime, in which the volumetric throughput of a Pd-supported silica monolith can be used to increase the quantity of the product without changing the optimal operating conditions. Two silica monoliths (both 3 cm long), with

• , respectively. Under optimal reaction conditions the quantity of product could be increased from 31 mg per hour to 340 mg per hour simply by changing the volumetric capacity of the monolith. Keywords: continuous flow; microwave heating; monolith; scaling-up; Suzuki–Miyaura reaction; Introduction Interest in

• heating. The practicality of this approach will be demonstrated using Suzuki–Miyaura reactions in which the Pd-supported silica-monolith catalysts exhibit excellent activities and the doubling of the monolith diameter, thus operating at four times the volumetric flow rate, increases product output without

Synthesis of chiral mono(N-heterocyclic carbene) palladium and gold complexes with a 1,1'-biphenyl scaffold and their applications in catalysis

• Lian-jun Liu,
• Feijun Wang,
• Wenfeng Wang,
• Mei-xin Zhao and
• Min Shi

Beilstein J. Org. Chem. 2011, 7, 555–564, doi:10.3762/bjoc.7.64

• '-biphenyl backbone have been prepared from chiral 6,6'-dimethoxybiphenyl-2,2'-diamine. The complexes were characterized by X-ray crystal structure diffraction. The Pd(II) complex showed good catalytic activities in the Suzuki–Miyaura and Heck–Mizoroki coupling reactions, and the (S)-Au(I) complexes also

• showed good catalytic activities in the asymmetric intramolecular hydroamination reaction to give the corresponding product in moderate ee. Keywords: chiral mono(N-heterocyclic carbene) complex; Heck–Mizoroki reaction; hydroamination; Suzuki–Miyaura reaction; Introduction N-heterocyclic carbene (NHC

• coupling reactions and a Au-catalyzed asymmetric reaction, respectively. Suzuki–Miyaura and Heck–Mizoroki coupling reactions catalyzed by NHC–Pd(II) complex The Pd-catalyzed coupling reaction is one of the most powerful methods for the formation of carbon–carbon bonds in organic synthesis [60][61][62][63

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

• Qingwei Du Yiqun Li Department of Chemistry, Jinan University, 510632 Guangzhou, China 10.3762/bjoc.7.48 Abstract A diphenylphosphinite cellulose palladium complex (Cell–OPPh2–Pd0) was found to be a highly efficient heterogeneous catalyst for the Suzuki–Miyaura reaction. The products were

• catalyst; Suzuki–Miyaura reaction; Introduction The formation of Csp2–Csp2 bonds has long remained a difficult task until the development of the Suzuki–Miyaura palladium-catalyzed reaction [1][2][3]. The palladium-catalyzed Suzuki cross-coupling reaction of aryl halides with arylboronic acids is one of

• . Moreover, it showed excellent catalytic activity in the Suzuki–Miyaura coupling reaction of various aryl haildes bearing electron-withdrawing and/or electron-donating groups. Results and Discussion Synthesis and characterization of Cell–OPPh2 and Cell–OPPh2–Pd0 It is well known that nanopalladium shows

Syntheses and properties of thienyl-substituted dithienophenazines

• Annemarie Meyer,
• Eva Sigmund,
• Friedhelm Luppertz,
• Gregor Schnakenburg,
• Immanuel Gadaczek,
• Thomas Bredow,
• Stefan-S. Jester and
• Sigurd Höger

Beilstein J. Org. Chem. 2010, 6, 1180–1187, doi:10.3762/bjoc.6.135

• quantitative yield [21][22]. The respective regio isomer 8 was synthesized starting from commercially available 3-bromothiophene 1 and boronic acid 5 in three steps (Scheme 2). By Suzuki–Miyaura coupling we obtained 3,3’-bithiophene in good yields. The red diketone 7 was prepared by two-fold acylation with

• and could be more easily purified by column chromatography. Nevertheless, both compounds can serve as starting materials for thiophene oligomers with increased donor ability. Thiophene- and bithiophene boronic acids or esters were coupled via Suzuki–Miyaura reactions forming orange-colored thiophene

• ). Suzuki–Miyaura reactions with 10a/10b. a) Pd(PPh3)4, Na2CO3, toluene, EtOH, H2O, reflux, 23% (12a), 36% (12b), 26% (13); b) Pd(PPh3)4, 1 M Cs2CO3, toluene, reflux, 19% (14), Pd(PPh3)4, 2 M Na2CO3, toluene, Aliquat 336, reflux, 21% (15). Suzuki–Miyaura reactions with 11a/11b. a) Pd(PPh3)4, Na2CO3, toluene

Suzuki–Miyaura cross-coupling reaction of 1-aryltriazenes with arylboronic acids catalyzed by a recyclable polymer-supported N-heterocyclic carbene–palladium complex catalyst

• Guangming Nan,
• Fang Ren and
• Meiming Luo

Beilstein J. Org. Chem. 2010, 6, No. 70, doi:10.3762/bjoc.6.70

• Suzuki–Miyaura cross-coupling reaction of 1-aryltriazenes with arylboronic acids catalyzed by a recyclable polymer-supported Pd–NHC complex catalyst has been realized for the first time. The polymer-supported catalyst can be re-used several times still retaining high activity for this transformation

• ; recyclable catalyst; Suzuki–Miyaura reaction; Introduction The unsymmetrical biaryls feature in a diverse range of organic compounds, such as natural products, advanced materials, liquid crystals, ligands and molecules of medicinal interest [1][2][3][4]. The palladium-catalyzed Suzuki–Miyaura cross-coupling

• reaction has evolved as a powerful synthetic tool for the synthesis of unsymmetrical biaryls in both academic laboratories and industry [5][6][7][8]. Most of the reported Suzuki–Miyaura reactions are based on the use of aryl halides and triflates, and recently sulfonates and carboxylates, as the

A short and efficient synthesis of valsartan via a Negishi reaction

• Samir Ghosh,
• A. Sanjeev Kumar and
• G. N. Mehta

Beilstein J. Org. Chem. 2010, 6, No. 27, doi:10.3762/bjoc.6.27

• synthesis of sartans: whilst the synthesis of losartan [4] as described in the literature makes use of Negishi [5][6] and Ullmann [7] couplings, the published methods for the preparation of valsartan utilize Suzuki–Miyaura couplings [8]. Of these, Negishi reactions have proved to be very efficient. However

Solvent-free and time-efficient Suzuki–Miyaura reaction in a ball mill: the solid reagent system KF–Al₂O₃ under inspection

• Franziska Bernhardt,
• Ronald Trotzki,
• Tony Szuppa,
• Achim Stolle and
• Bernd Ondruschka

Beilstein J. Org. Chem. 2010, 6, No. 7, doi:10.3762/bjoc.6.7

• KF-loaded aluminas is available in the literature, there is almost no data concerning the influence of parameters such as alumina modification or KF-loading on experimental results. Hence, the Pd-catalyzed, solvent-free Suzuki–Miyaura reaction was chosen as model reaction to investigate the effect of

• applied in solvent-free Pd-catalyzed Suzuki–Miyaura cross-coupling reactions of aryl bromides with phenylboronic acid, and the performances of the individual SRS were compared [33][34][36][37][38][39][40][41][42]. Results and Discussion Incorporation of KF–Al2O3 as a basic component in organic synthesis

• pH measurements of aqueous suspension of the pure aluminas. Investigating the influence of different SRS, the Pd(OAc)2-assisted Suzuki–Miyaura coupling of phenylboronic acid (1) with different aryl bromides 2 furnishing p-substituted biphenyls 3 (Scheme 1) was chosen. Reactions were performed in a

Diastereoselective functionalisation of benzo-annulated bicyclic sultams: Application for the synthesis of cis-2,4-diarylpyrrolidines

• Susan Kelleher,
• Pierre-Yves Quesne and
• Paul Evans

Beilstein J. Org. Chem. 2009, 5, No. 69, doi:10.3762/bjoc.5.69

• above proving inefficient, palladium chemistry was subsequently considered. The vinyl bromide 24a was reported to participate in Sonagashira alkynylation chemistry; however, yields of the resultant enyne were low [20]. Therefore, we decided to investigate Suzuki–Miyaura cross-coupling reaction as a

• . Possible explanation for the products formed in the dibromination of 5a and 5b. Lithiation–CO2 quench approach for the synthesis of 26 from vinyl bromide 24a. Suzuki–Miyaura cross-coupling of 24a and the diastereoselective hydrogenation of the resultant styrene adducts. Attempted sulfonamide double

Gold film- catalysed benzannulation by Microwave- Assisted, Continuous Flow Organic Synthesis (MACOS)

• Gjergji Shore,
• Michael Tsimerman and
• Michael G. Organ

Beilstein J. Org. Chem. 2009, 5, No. 35, doi:10.3762/bjoc.5.35

• Suzuki–Miyaura and Heck reactions, i.e., Pd-thin films promote these transformations without any additional catalyst being added to the reactant stream(s) that enter the flow tube [28]. Without microwave irradiation, the above-described cross-coupling reactions did not proceed indicating that there is

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

• heterogeneous supports for palladium(0) nanoparticles is described. These functionalized polymers were incorporated inside a flow reactor and employed in Suzuki–Miyaura and Heck cross couplings under continuous flow conditions. Keywords: Heck–Mizoroki reaction; heterogeneous catalysis; ion exchange resin

• ; microreactor; monolith; palladium; Suzuki–Miyaura reaction; Introduction Functionalized solid supports like polymers loaded with homogeneous catalysts are well established in organic synthesis [1][2][3][4]. Simple purification of the products and easy recyclability of the catalysts are major advantages of

• nanoparticles (7–10 nm in size and a palladium content of 0.03 weight% Pd on polyionic polymer). Suzuki–Miyaura cross coupling reactions In our earlier work we showed that these materials are well suited for transfer hydrogenations under flow conditions [23][24]. Recently, the Suzuki–Miyaura reaction and other

Oxidative cyclization of alkenols with Oxone using a miniflow reactor

• Yoichi M. A. Yamada,
• Kaoru Torii and
• Yasuhiro Uozumi

Beilstein J. Org. Chem. 2009, 5, No. 18, doi:10.3762/bjoc.5.18

• laminar flow interface [16], resulting in the instantaneous production of biaryls (quantitative yield within 4 s of residence time) via a palladium-catalyzed Suzuki-Miyaura reaction under microflow conditions. An additional advantage of micro- and minireactors is the small heat capacity of the micro- and

Convenient methods for preparing π-conjugated linkers as building blocks for modular chemistry

• Jiří Kulhánek,
• Filip Bureš and
• Miroslav Ludwig

Beilstein J. Org. Chem. 2009, 5, No. 11, doi:10.3762/bjoc.5.11

• use as building blocks in Suzuki–Miyaura or Sonogashira coupling reactions. Keywords: boronic acid; donor/acceptor; linker; Sonogashira reaction; property tuning; push-pull; Suzuki–Miyaura reaction; Introduction Development of new organic compounds with improved and advanced properties is one of the

• moieties is usually accomplished by cross-coupling reactions, in particular by the Suzuki–Miyaura [26][27] or the Sonogashira [28] reactions. Consequently, the availability of the suitably substituted π-conjugated linkers of various lengths bearing boronic ester functionality or terminal acetylene is

• crucial for such a synthetic approach. Hence, we report here a convenient synthesis as well as characterization of either unsubstituted (R = H) or donor substituted (R = NMe2, OMe) π-conjugated linkers designed for the Suzuki–Miyaura and Sonogashira cross-couplings with a systematically varied and

Mechanistic aspects of the isomerization of Z-vinylic tellurides double bonds in the synthesis of potassium Z-vinyltrifluoroborate salts

• Hélio A. Stefani,
• Rafael C. Guadagnin,
• Artur F. Keppler,
• Giancarlo V. Botteselle,
• João V. Comasseto and
• Carlos A. Suganuma

Beilstein J. Org. Chem. 2008, 4, No. 9, doi:10.1186/1860-5397-4-9

• acids and boronate esters are the most commonly used derivatives in Suzuki-Miyaura cross-coupling reactions. Recently, Molander et al. [1] and our group [2] have explored the use of potassium organotrifluoroborate salts as an alternative to the usual organoboron reagents in alkenyl-alkenyl [3], aryl