Synthesis and antifungal properties of papulacandin derivatives

• Marjolein van der Kaaden,
• Eefjan Breukink and
• Roland J. Pieters

Beilstein J. Org. Chem. 2012, 8, 732–737, doi:10.3762/bjoc.8.82

• spiroketal unit, which is introduced in a palladium-catalyzed cross-coupling reaction of a glycal silanolate and an aryl iodide followed by an oxidative spiroketalization. Four different variants were made, differing in the nature of the acyl side chain with respect to the length, and in the number and

• gave a mixture of products. Finally, compound 21 was oxidized to give silanol building block 22. With building blocks 13 and 22 in hand, the palladium-catalyzed cross-coupling reaction was performed by using Pd2(dba)3 to give 23 (Scheme 3). Then the pivaloyl ester was selectively cleaved by using DIBAL

Sonogashira–Hagihara reactions of halogenated glycals

• Dennis C. Koester and
• Daniel B. Werz

Beilstein J. Org. Chem. 2012, 8, 675–682, doi:10.3762/bjoc.8.75

• glycals using several aromatic and aliphatic alkynes. This Pd-catalyzed cross-coupling reaction presents a facile access to alkynyl C-glycosides and sets the stage for a reductive/oxidative refunctionalization of the enyne moiety to regenerate either C-glycosidic structures or pyran derivatives with a

• cross-coupling reaction with iodoarenes. However, it is not only metalated sugar derivatives that have prevailed in the synthesis of C-glycosides, but also some electrophilic coupling reagents, such as glycalyl phosphates, and bromo- and iodoglycals. Glycal phosphates of type 5 were employed as

• electrophiles in a Stille cross-coupling reaction [18]. These building blocks exhibit a high stability and efficiency in their formation and are therefore particularly interesting. In a careful optimization study, Tan and co-workers found that several alkenes hydroborated in situ with 9-BBN can be utilized in a

Syntheses and applications of furanyl-functionalised 2,2’:6’,2’’-terpyridines

• Jérôme Husson and
• Michael Knorr

Beilstein J. Org. Chem. 2012, 8, 379–389, doi:10.3762/bjoc.8.41

• dihydropyridine 32. The latter undergoes aromatization upon reaction with benzoquinone to afford 33 (Scheme 6). Synthesis by cross-coupling reaction Cross-coupling reactions are widely used in organic chemistry [32] to create new C–C bonds. The importance of this technique was recently highlighted by the award of

• . Synthesis of tpy by Stille cross-coupling reaction. Oxidation of the furan ring of furanyl-substituted terpyridines. Direct oxidation of a furan ring attached on Ru(II) tpy complexes. Synthetic pathway to europium(III) and samarium(III) chelates 56 and 57. Synthetic pathway to prepare thiocyanato

Synthesis of multivalent host and guest molecules for the construction of multithreaded diamide pseudorotaxanes

• Nora L. Löw,
• Egor V. Dzyuba,
• Boris Brusilowskij,
• Lena Kaufmann,
• Elisa Franzmann,
• Wolfgang Maison,
• Emily Brandt,
• Daniel Aicher,
• Arno Wiehe and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2012, 8, 234–245, doi:10.3762/bjoc.8.24

• attempts to use the same conditions for the fourfold coupling of 1 to 15 to synthesize tetravalent wheel 16 were unsuccessful, and we finally used another procedure for the cross-coupling reaction [107]. Because the Cu(I) catalyst may interfere with the Zn core of porphyrin 15 or lead to Glaser coupled

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

• -metallated oxazole with its ring-open tautomer [67]. Using Pd(0)/Cu(I) catalysis, the C2-cuprated oxazole may act as a transmetallating agent through a standard cross-coupling reaction (Scheme 18, route B) [67]. Under Pd(0)- and Cu(I)-free catalysis, Zhuralev identified a cross-coupling-type mechanism for

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

• iPrMgCl·LiCl (64) at −40 °C for 1 h leading to an intermediate magnesium reagent, which after transmetalation to the corresponding zinc reagent using ZnBr2 provides, after Negishi cross-coupling reaction with the bromoquinoline 80, the polyfunctinal triazene 81 in 75% yield. The conversion of the triazene

• functionalization of heterocycles such as the dicarbethoxypyridine 133, which is readily magnesiated with the base 129 at −40 °C within 3 h, leading to 134. After a Negishi cross-coupling reaction with an aromatic iodide, the 2-functionalized pyridine 135 is obtained in 73% yield (Scheme 21, Procedure 8) [49]. 3

• that the presence of iPrI (or another alkyl iodide) catalyzes the Kumada cross-coupling reaction, such that highly reactive functional groups, such as ketones, esters or nitriles, are perfectly tolerated (Scheme 24 and Supporting Information File 1, Procedure 10) [57][58]. The mechanism of the reaction

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

• homogeneous gold-catalyzed oxidative cross-coupling which leads to α-arylenones 190 from propargylic acetates 189 and arylboronic acids has been developed by Zhang’s group (Scheme 35) [86]. This cross-coupling reaction reveals the synthetic potential of Au(I)/Au(III) catalytic cycles. Kimber reported a facile

• (Scheme 53). The latter is the first example of a gold-catalyzed intramolecular C–C cross-coupling reaction involving aryl C–H functionalization with Selectfluor® as the oxidant. 2,4-Dien-6-ynecarboxylic acids 316 undergo gold-catalyzed tandem 1,6-cyclization/decarboxylation to afford 2,3-disubstituted

Nano copper oxide catalyzed synthesis of symmetrical diaryl sulfides under ligand free conditions

• K. Harsha Vardhan Reddy,
• V. Prakash Reddy,
• A. Ashwan Kumar,
• G. Kranthi and
• Y.V.D. Nageswar

Beilstein J. Org. Chem. 2011, 7, 886–891, doi:10.3762/bjoc.7.101

• , entries 1 and 2). The ideal temperature for the reaction was found to be 130 °C. A study was conducted on C–S cross-coupling reaction using various sulfur sources under these conditions (Table 2). Among these sulfur surrogates potassium thiocyanate gave good yields in this C–S cross-coupling reaction

• identity and purity of the product was confirmed by 1H and 13C NMR spectroscopy. Synthesis of symmetrical aryl sulfides catalyzed by copper oxide nanoparticles. Screening of copper sources for the cross-coupling reaction between iodo benzene and potassium thiocyanate.a Nano CuO catalyzed C–S cross-coupling

Au(I)/Au(III)-catalyzed Sonogashira-type reactions of functionalized terminal alkynes with arylboronic acids under mild conditions

• Deyun Qian and
• Junliang Zhang

Beilstein J. Org. Chem. 2011, 7, 808–812, doi:10.3762/bjoc.7.92

• , Chinese Academy of Sciences, Ling Ling Road 345 Shanghai 200032 (P. R. China) 10.3762/bjoc.7.92 Abstract A straightforward, efficient, and reliable redox catalyst system for the Au(I)/Au(III)-catalyzed Sonogashira cross-coupling reaction of functionalized terminal alkynes with arylboronic acids under

• existence of Au(I)/Au(III) catalytic cycles [26][27][28][29][30][31][32]. For instance, Zhang and co-workers have developed a gold-catalyzed oxidative cross-coupling reaction of arylboronic acids with propargyl esters [27], and Selectfluor® – a source of electrophilic fluorine – was used to oxidize the

• presence of oxidant (Selectfluor®) and base, and undergo a Au(I)/Au(III)-catalyzed Sonogashira-type cross-coupling reaction (Scheme 1). Results and Discussion We embarked on developing a general protocol for Sonogashira-type cross-coupling by using propargyl tosylamide (1a) and phenylboronic acid as the

Synthesis, reactivity and biological activity of 5-alkoxymethyluracil analogues

• Lucie Brulikova and
• Jan Hlavac

Beilstein J. Org. Chem. 2011, 7, 678–698, doi:10.3762/bjoc.7.80

• monophosphates. Almost 10 years earlier, Bergstrom and co-workers published a synthesis based on the same reaction – the Heck cross-coupling reaction of an alkene with an organometallic derivative [41] in which two pyrimidine nucleosides were coupled (Scheme 27). Thus, 5-(chloromercuri)-2'-deoxyuridine was

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

• 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

• diphenylphosphinite cellulose-supported nanopalladium catalyst, it was initially used in the Suzuki–Miyaura cross-coupling reaction, which is a versatile and a well studied method for the generation of Csp2–Csp2 bonds in organic synthesis. The influence of base, solvent and amount of catalyst on Suzuki–Miyaura cross

• –Pd0). General procedure for the Suzuki–Miyaura cross-coupling reaction In a typical experiment, the Cell–OPPh2–Pd0 catalyst (0.005 mmol of Pd) was added to a mixture of aryl halide (1.0 mmol), arylboronic acid (1.2 mmol), and K2CO3 (2.0 mmol) in 95% ethanol (5 cm3), and the reaction mixture was

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

• , and NMR. The effect of different solvents on the Suzuki coupling reactiona. The effect of various bases on the Suzuki coupling reactiona. The effect of various temperatures on the Suzuki coupling reactiona. Suzuki cross coupling reaction of aryl halides with arylboronic acida. Suzuki cross coupling

• reaction of di- and trihaloaryls with arylboronic acida. Supporting Information Scanning electron microscope image, X-ray photoemission spectrum, X-ray powder diffraction pattern, catalytic activity of different loading of palladium over NiFe2O4, catalyst recycling studies and 1H and 13C NMR for the

Ene–yne cross-metathesis with ruthenium carbene catalysts

• Cédric Fischmeister and
• Christian Bruneau

Beilstein J. Org. Chem. 2011, 7, 156–166, doi:10.3762/bjoc.7.22

• hindered diene with the carbonate group and the aliphatic chain connected to the same double bond gave a trisubstituted olefin, which indicated a regioselective cross-coupling reaction. On the other hand, the stereoselectivity of the 1,2-disubstituted double bond was not controlled. Under the conditions

• economy. It has not been developed as rapidly as the olefin cross-metathesis because it suffers from some reactivity and selectivity issues that have not yet been solved. Regioselectivity of the cross-coupling reaction is usually good as no problem is encountered starting from symmetrical alkynes; and in

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

• electrophilic component [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. As an additional candidate for the electrophilic coupling partner, arenediazonium salts have also been used in place of aryl halides in the Suzuki–Miyaura cross-coupling reaction, and show higher activity than the corresponding aryl

• arenediazonium salt surrogates in the Suzuki–Miyaura cross-coupling reaction [29]. Pd2(dba)3 and P(tBu)3 were used as catalyst in this reaction where, as in most of homogeneous catalytic systems, the difficulties of catalyst recovery and recycling constitute major problems. One possible solution to these

Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides

• Ana Maria Castilla,
• M. Morgan Conn and
• Pablo Ballester

Beilstein J. Org. Chem. 2010, 6, No. 5, doi:10.3762/bjoc.6.5

• , iodo-aryl 4 and trimethylstannyl-aryl 5, following experimental procedures described in recent literature reports [23]. Synthesis The synthetic strategy designed for the construction of receptors 1 and 2 involves the use of a carbonylative cross-coupling reaction between two aryl derivatives (iodo-aryl

• , and sulfuric acid (Scheme 1). We obtained (S)-6 in enantiomerically pure form in 50% yield. Since we plan to assemble the 4,4’-bis(alanyl)benzophenones 3 by a Stille carbonylative cross-coupling reaction, the required trimethylstannyl derivatives 5 should be easily prepared from adequately diprotected

• phenylalanine iodides 4 (Scheme 1). The mild reaction conditions used in the carbonylative cross-coupling permit the use of common protecting groups of peptide synthesis [24]. This characteristic of the carbonylative cross-coupling reaction allowed us to achieve the differential protection of the two amino acid

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

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

• 0.7 ppm for each run. This very low value for leaching corresponds to the leaching determined for transfer hydrogenations with this catalytic flow system using cyclohexene as hydrogen source and solvent [23][24]. Heck–Mizoroki reactions One other very important cross coupling reaction that bears

Synthesis and redox behavior of new ferrocene- π-extended- dithiafulvalenes: An approach for anticipated organic conductors

• Abdelwareth A. O. Sarhan,
• Omar F. Mohammed and
• Taeko Izumi

Beilstein J. Org. Chem. 2009, 5, No. 6, doi:10.3762/bjoc.5.6

• the modified Wittig–Horner cross-coupling reaction using n-BuLi/THF at temperature varies from −78 °C to 0 °C. These new classes of bis(1,3-dithiafulvalene)ferrocenes have the 1,3-dithiole ring system separated by ferrocene as conjugated spacer. The ferrocene-dithiafulvalenes derivatives 9 and 12 were

• these systems [27]. Results and Discussion In this work we synthesized a series of novel 1,1′-bis[(1,3-dithiol-2-ylidene)heteroaryl/aryl]ferrocene [1,1′-bis(1,3-DTF)Fc] derivatives as new electron donor compounds using the direct Wittig–Horner cross coupling reaction. The starting 1,1′-diacylferrocene

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

• synthesized by Wu’s group in 1999 [30] which used a palladium-catalyzed cross-coupling reaction between the butenolide 39 and the THF unit 22 as the key step for constructing the backbone of 36 (Scheme 5). The synthesis of aldehyde 37 began with D-xylose and involved construction of a γ-lactone moiety

• utilizing Wu’s own methodology. Wittig reaction of the aldehyde 37 and the Wittig reagent 38 furnished the butenolide unit 39. The tetrahydrofuran part of 22 was constructed from D-glucose via epoxide 40. The entire carbon skeleton of 41 was constructed by Pd(0)-catalyzed cross-coupling reaction between 39

• synthesis, diastereoselective epoxidation of 72 and spontaneous cyclization afforded the diastereomers 73a and 73b. Protection of the hydroxyl group of 73a as a MOM ether afforded 74, which was coupled with the γ-lactone precursor 75 by a Sonogashira cross-coupling reaction to give compound 76. Catalytic

N-Arylation of amines, amides, imides and sulfonamides with arylboroxines catalyzed by simple copper salt/EtOH system

• Zhang-Guo Zheng,
• Jun Wen,
• Na Wang,
• Bo Wu and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2008, 4, No. 40, doi:10.3762/bjoc.4.40

• are the most used aryl donors in the cross-coupling reaction. However, these reactions were carried out with Et3N [8][9][10], pyridine [10][11][12][13], or TMEDA [14] as base, or addition of ligand [15]. These procedures usually also used a halogenated hydrocarbon as solvent [8][9][10][11][12

• recently in the mechanism of the cross-coupling reaction based on boronic acid. The group of Chan has reported the dynamic behavior of boronic acid in the copper salt catalytic system. The results implied that the active arylating agent such as arylboronic acid in the cross-coupling reaction is indeed its

• anhydride form (boroxine) and not the free acid [21]. This result prompted us to study arylboroxines as aryl donors instead of arylboronic acids in the cross-coupling reaction, since arylboroxine is more active and may remarkably accelerate the reaction. In this paper we found that N-arylation reaction can

Synthesis of deep- cavity fluorous calix[4]arenes as molecular recognition scaffolds

• Maksim Osipov,
• Qianli Chu,
• Steven J. Geib,
• Dennis P. Curran and
• Stephen G. Weber

Beilstein J. Org. Chem. 2008, 4, No. 36, doi:10.3762/bjoc.4.36

• showed diminished yields due to product occlusion with the precipitation of silver iodide. The reactivity of 5 in the Kumada cross-coupling reaction was next investigated. Treatment of 5 with PdCl2(dppf) followed by phenylmagnesium bromide provided the biaryl 6 as the only observed product in 75% yield