Rapid regio- and multi-coupling reactivity of 2,3-dibromobenzofurans with atom-economic triarylbismuths under palladium catalysis

• Maddali L. N. Rao,
• Jalindar B. Talode and
• Venneti N. Murty

Beilstein J. Org. Chem. 2016, 12, 2065–2076, doi:10.3762/bjoc.12.195

• trial reaction was performed with 2,3-dibromobenzofuran (1.1, 3.3 equiv) and tri(p-anisyl)bismuth (1 equiv) with Pd(OAc)2/PPh3, Cs2CO3 (3 equiv) in N-methyl-2-pyrrolidone (NMP) at 90 °C for 1 h as protocol conditions [35]. This protocol furnished the preferential cross-coupling at the more electrophilic

• could be obtained in excellent yield with Pd(OAc)2/4 PPh3 (0.1 equiv) Cs2CO3 (4 equiv) in NMP at 90 °C and 2 h reaction time (Table 1, entry 3) and it was considered as optimized protocol for our further study. To check the generality of this regio-selective coupling, various 2,3-dibromobenzofurans have

Flow carbonylation of sterically hindered ortho-substituted iodoarenes

• Carl J. Mallia,
• Gary C. Walter and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2016, 12, 1503–1511, doi:10.3762/bjoc.12.147

• fixed 5 mol % of Pd(OAc)2 and 10 mol % of the phosphine ligand was investigated. It was noted that the catalyst level could be reduced [34], but this amount allowed for an efficient catalytic process with short reaction times in the region of two hours, a good match for the flow system assembly [8

Synthesis of 2-substituted tetraphenylenes via transition-metal-catalyzed derivatization of tetraphenylene

• Shulei Pan,
• Hang Jiang,
• Yanghui Zhang,
• Yu Zhang and
• Dushen Chen

Beilstein J. Org. Chem. 2016, 12, 1302–1308, doi:10.3762/bjoc.12.122

• tetraphenylene (1). For this, 1 was allowed to react with PhI(OAc)2 (2a) in the presence of Pd(OAc)2/pyridine as catalysis system in a mixture of AcOH and Ac2O at 100 °C. Gratefully, the desired acetylated product 3a was formed in 52% yield (Table 1, entry 1). Prolonging the reaction time or carrying out the

• promote the reaction. Therefore, we screened the effect of different co-solvents on the reaction and dichloromethane was found to be the best choice (Table 5, entries 4 and 5). The yield was remarkably improved by increasing the amount of Pd(OAc)2 (Table 5, entry 6). Raising or lowering the temperature

• methods for the synthesis of a variety of 2-substituted tetraphenylenes, which could accelerate the research on the properties and application of tetraphenylene derivatives. Tetraphenylene and its saddle-shaped structure. The Pd(OAc)2-catalyzed reaction of nitriles with tetraphenylene (1). The Pd(OA)2

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

• Mohammad Haji

Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121

• one-pot reaction of carbodiimide 197, isocyanide 199 and dialkyl phosphonates 198 under optimized conditions (10 mol % of Pd(OAc)2, 10 mol % of FeCl3, 10 mol % of DPPF, 3.0 equiv of Cs2CO3, toluene, reflux) led to (4-imino-3,4-dihydroquinazolin-2-yl)phosphonates 203 in 37–78% yields (Scheme 42). This

Palladium-catalyzed picolinamide-directed iodination of remote ortho-C−H bonds of arenes: Synthesis of tetrahydroquinolines

• William A. Nack,
• Xinmou Wang,
• Bo Wang,
• Gang He and
• Gong Chen

Beilstein J. Org. Chem. 2016, 12, 1243–1249, doi:10.3762/bjoc.12.119

• diverse substitution patterns from readily accessible starting materials. New synthetic strategy for THQs via PA-directed C−H functionalization. Preparation of iodo-substituted THQs via PA-directed C−H functionalization strategy. a) ArI (2 equiv), Pd(OAc)2 (10 mol %), (BnO)2PO2H (20 mol %), Ag2CO3 (1.5

• equiv), t-AmylOH, 110 °C, 24h; b) Pd(OAc)2 (10 mol %), I2 (4 equiv), PhI(OAc)2 (4 equiv), KHCO3 (1 equiv), 130 °C, DMF, 24 h; c) NIS (1.1 equiv), HBF4.OEt2 (4), TFA/DCM (1:9), 2.5 mM, 0 °C, 4 h; d) CuI (10 mol %), CsOAc (2.5 equiv), DMSO, Ar, 90 °C, 20 h; e) NIS (1.1 equiv), TFA/DCM (1:9), 2.5 mM, rt

• , 16 h; f) Pd(OAc)2 (15 mol %), NIS (2.5 equiv), α,α,α-trifluorotoluene, Ar, 100 °C, 24 h. Removal of PA auxiliary from THQ product. Optimization of Pd-catalyzed ortho C−H iodination of 5.a Substrate scope of Pd-catalyzed ε-C−H iodination and Cu-catalyzed C−N cyclization to form THQsa. Supporting

Synthesis of β-arylated alkylamides via Pd-catalyzed one-pot installation of a directing group and C(sp³)–H arylation

• Yunyun Liu,
• Yi Zhang,
• Xiaoji Cao and
• Jie-Ping Wan

Beilstein J. Org. Chem. 2016, 12, 1122–1126, doi:10.3762/bjoc.12.108

• a model reaction. The primary reaction in the presence of Pd(OAc)2 provided smoothly the target product 4a (entry 1, Table 1). The variation in the effect of catalyst loading proved that 5 mol % was proper (entries 2 and 3, Table 1). Further investigations using different palladium catalysts such as

Cationic Pd(II)-catalyzed C–H activation/cross-coupling reactions at room temperature: synthetic and mechanistic studies

• Takashi Nishikata,
• Alexander R. Abela,
• Shenlin Huang and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2016, 12, 1040–1064, doi:10.3762/bjoc.12.99

• arylureas at room temperature. A commercially available catalyst [Pd(MeCN)4](BF4)2 or a nitrile-free cationic palladium(II) complex generated in situ from the reaction of Pd(OAc)2 and HBF4, effectively catalyzes C–H activation/cross-coupling reactions between aryl iodides, arylboronic acids and acrylates

• . Although the combination of acetanilide together with a palladium(II) catalyst lead to the corresponding palladacycle, as reported by Tremont [172], in the presence of 2a, Pd(OAc)2, HBF4 and AgOAc at room temperature, acetyl or isopropyl anilides afford essentially no product. Only after heating to 50 °C

• were examined, such as Pd(OAc)2, PdCl2Ln, Pd2(dba)3, in the absence of added acid, but none led to cross-coupling at room temperature. 1,4-Benzoquinone (BQ) was found to be an effective additive in promoting the reaction, while addition of stoichiometric metal salts (e.g., silver or copper salts) was

A convenient route to symmetrically and unsymmetrically substituted 3,5-diaryl-2,4,6-trimethylpyridines via Suzuki–Miyaura cross-coupling reaction

• Dariusz Błachut,
• Joanna Szawkało and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2016, 12, 835–845, doi:10.3762/bjoc.12.82

• . The screening was then continued with Pd(OAc)2 and tri-(o-tolyl)phosphine (P(o-tol)3) used as a catalyst in the mixture toluene/water/ethanol as solvent system and with sodium carbonate as a base. In order to control the progress of the process, the mixture was regularly sampled and the components

• leading to a more active monophosphine Pd complex. In our case, tricyclohexylphosphine associated with Pd(OAc)2 in toluene/H2O/EtOH confirmed its utility as a powerful catalytic system, giving fast and clean conversion of substrate 1 within 2–3 hours. When the reaction was performed with 2.8 equiv of

• phenylboronic acid in the presence of Pd(OAc)2/P(Cy)3, the final diarylpyridine 4 was obtained in each case in very good yield (95–99%, Table 1, entries 21–26) and the outcome of the reaction was independent on the base and the solvent used. The only exception was entry 27, where CsF as a mild base was applied

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

• same product in much higher yields such as 90 and 93% under reaction conditions of 1 mol % of Pd(OAc)2, 1 mol % of 1 and 2, KOH, DMF/H2O within a short period of time (1 h) at 80 °C. The synthesized carbene precursors consist of an electron-neutral group (benzyl), electron-donating group (3

• –NHC complex as catalyst resulted in low yields and conversions (Table 3, entries 9–12). The usage of the morpholinoethyl substituted benzimidazolium compound 4 with Pd(OAc)2 resulted in higher yields of 2-(4-nitrophenyl)benzo[b]thiophene compared to the usage of compounds 1–3. Generally, the PEPPSI Pd

Selectively fluorinated cyclohexane building blocks: Derivatives of carbonylated all-cis-3-phenyl-1,2,4,5-tetrafluorocyclohexane

• Mohammed Salah Ayoup,
• David B. Cordes,
• Alexandra M. Z. Slawin and
• David O'Hagan

Beilstein J. Org. Chem. 2015, 11, 2671–2676, doi:10.3762/bjoc.11.287

• an electrostatically positive (δ +ve) hydrogen face. X-ray structure of aldehyde 15. CCDC number 1432193. Preparation of benzoic acids 11–13; i. HIO4·2H2O (50%), AcOH, H2SO4, I2, H2O, 70 °C 24 h, 92%.; ii. Pd(OAc)2, Ph3P,Et3N, EtOH, CO (1 atm), 80 °C, 16 h. iii. HCl (6 M), 1,4-dioxane, 70 °C, 24 h or

Stereoselective synthesis of hernandulcin, peroxylippidulcine A, lippidulcines A, B and C and taste evaluation

• Marco G. Rigamonti and
• Francesco G. Gatti

Beilstein J. Org. Chem. 2015, 11, 2117–2124, doi:10.3762/bjoc.11.228

• [26][27], indeed when 10 was treated with a substoichiometric amount of Pd(OAc)2 in DMSO at 58 °C under an oxygen atmosphere, it was possible to isolate 11 ([α]D +11.1° (c 1.4, CHCl3), vs lit. [13] [α]D +9.7° (c 0.14, EtOH)) in a maximum yield of 54%, as no starting material was present anymore in the

• reaction mixture. Very recently, Stahl et al. have proved that by replacing Pd(OAc)2 with Pd(TFA)2 it is possible to dehydrogenate directly the ketones at room temperature [28], but without the possibility of controlling the regioselectivity. Since, in our case this issue is critical we tried to apply the

• dehydrogenations (mainly DMSO or MeCN); even when using mixed co-solvent systems, the results were still very poor. Next, we tested the Tsuji variant [30] (Pd(OAc)2, dppe, diallyl carbonate, MeCN) but both 10 and 10a decomposed during the reaction. Finally, (+)-hernandulcin 1 was obtained in a 92% yield by

Efficient synthesis of π-conjugated molecules incorporating fluorinated phenylene units through palladium-catalyzed iterative C(sp²)–H bond arylations

• Fatiha Abdelmalek,
• Fazia Derridj,
• Safia Djebbar,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2015, 11, 2012–2020, doi:10.3762/bjoc.11.218

• of heteroarylated polyfluorobiphenyls in good yields via two or three sequential iterative palladium-catalyzed direct arylations. Different pathways for the synthesis of π-conjugated molecules incorporating fluorinated phenylene units. i) Pd(OAc)2, KOAc, DMA, 150 °C. ii) PdCl(C3H5)(dppb), KOAc, DMA

Pyridine-promoted dediazoniation of aryldiazonium tetrafluoroborates: Application to the synthesis of SF₅-substituted phenylboronic esters and iodobenzenes

• George Iakobson,
• Junyi Du,
• Alexandra M. Z. Slawin and
• Petr Beier

Beilstein J. Org. Chem. 2015, 11, 1494–1502, doi:10.3762/bjoc.11.162

• aryldiazonium tetrafluoroborates with NHC-Pd catalysts was reported recently [63]. When applied to 3a and 3b using Pd(OAc)2 and NHC ligand precursors L, the borylated products 2a and 2b were isolated in only moderate yields (Table 2, entries 1 and 2). However, it was found that the Pd catalyst was not required

• potassium SF5-phenyltrifluoroborates were found to be highly reactive with a variety of aryl bromides and iodides in the presence of catalytic amounts of PdCl2(dppf)·CH2Cl2 or Pd(OAc)2 [72]. The recently published synthesis of arylboronic acids from anilines or aryldiazonium tetrafluoroborates using B2(OH)4

Pd(OAc)₂-catalyzed dehydrogenative C–H activation: An expedient synthesis of uracil-annulated β-carbolinones

• Biplab Mondal,
• Somjit Hazra,
• Tarun K. Panda and
• Brindaban Roy

Beilstein J. Org. Chem. 2015, 11, 1360–1366, doi:10.3762/bjoc.11.146

• .11.146 Abstract An intramolecular dehydrogenative C–H activation enabled an efficient synthesis of an uracil-annulated β-carbolinone ring system. The reaction is simple, efficient and high yielding (85–92%). Keywords: β-carbolinones; cyclization; dehydrogenative C–H activation; Pd(OAc)2; uracil

• base. The amide precursor was then subjected to a series of reactions in pursuit of the best reaction conditions for the dehydrogenative cross-coupling process. Assuming that the reaction goes through an electrophilic metallation pathway, it was projected that Pd(OAc)2 would be an excellent starting

• point for catalyst screening. The amide 4a (R1 = R2 = R3 = R4 = Me) was used as a model substrate for this dehydrogenative coupling reaction. The reaction was set up in the presence of Pd(OAc)2 (10 mol %), Cu(OAc)2 (2 equiv) in DMF under open air at 70 °C (Table 1, entry 1). After 8 h we obtained 35

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• , reduction with LiAlH4, reductive amination and allylation that afforded the indole derivatives 63 (18%) and N-Boc protected compound 68 (23%). The reaction of 63 with Pd(OAc)2 (25 mol %) and tri(o-tolyl)phosphine (55 mol %) at reflux gave 9-endo-64a (24%) and 8-exo-65b (21%). However, the compound 68 under

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• reaction mixture at room temperature [29]. In the light of these results, we also attempted to carry out this process under milder conditions. When (S)-4-isopropyl-2-(naphthalen-1-yl)oxazoline (2) was added to an acetic acid solution of Pd(OAc)2, a yellowish precipitate was obtained and identified as (S,S

• six-membered 5b. Indeed, palladium insertion in the peri C–H bond of the naphthyl-oxazoline will take place at high temperature reactions [32]. In order to investigate the effect of solvents on the isomeric ratio, cyclopalladation of oxazoline 2 was also carried out with Pd(OAc)2 in refluxing MeCN

• cyclopalladated complexes Synthesis of (S)-chloro-[(4-isopropyloxazolinyl)-2-naphthyl](triphenylphosphine)palladium(II) (5): The complex (3) was synthesized using two methods: Method A: A mixture of Pd(OAc)2 (50 mg, 0.22 mmol, 1 equiv), AcONa (18.3 mg, 0.22 mmol, 1 equiv) and (S)-4-isopropyl-2-(naphthalen-1-yl

Reactions of nitroxides 15. Cinnamates bearing a nitroxyl moiety synthesized using a Mizoroki–Heck cross-coupling reaction

• Jerzy Zakrzewski and
• Bogumiła Huras

Beilstein J. Org. Chem. 2015, 11, 1155–1162, doi:10.3762/bjoc.11.130

• -tetramethylpiperidine-1-oxyl (3) with iodobenzene (4a) and 4-methyliodobenzene (4b) were used as the test reactions to check the effectiveness of various palladium catalyst systems. The use of Pd(OAc)2/Ph3P/Bu3N [37] resulted in a low yield of the target products. No products were obtained when other catalyst systems

Radical-mediated dehydrative preparation of cyclic imides using (NH₄)₂S₂O₈–DMSO: application to the synthesis of vernakalant

• Dnyaneshwar N. Garad,
• Subhash D. Tanpure and
• Santosh B. Mhaske

Beilstein J. Org. Chem. 2015, 11, 1008–1016, doi:10.3762/bjoc.11.113

• (OAc)2 (10 mol %), ammonium persulfate (APS) (2 equiv), 1,4-dioxane (0.1 M), DMSO (5% v/v), 100 °C, 3 h in a Schlenk tube). A practical synthesis of vernakalant (11). Optimization studiesa. Imides from substituted/unsubstituted aromatic amines and succinic anhydridesa. Imides from substituted

• are exploring the application of this newly developed protocol for the synthesis of other hetereocyclic compounds, natural products, drugs and polyimides. Natural products and drugs featuring imide core. Radical trapping experiment. Attempted methodology and its outcome (reaction conditions: (a) Pd

Highly selective palladium–benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions

• Antonio Monopoli,
• Pietro Cotugno,
• Carlo G. Zambonin,
• Francesco Ciminale and
• Angelo Nacci

Beilstein J. Org. Chem. 2015, 11, 994–999, doi:10.3762/bjoc.11.111

• conventional solvents [37] and in ionic liquids [38]. Complex I is easily prepared from the corresponding thiazolium salt V and Pd(OAc)2, and due to its high stability the complex can be purified by silica gel chromatography. We report here the use of dicarbenediiodopalladium(II) complex I, prepared in situ

Chiroptical properties of 1,3-diphenylallene-anchored tetrathiafulvalene and its polymer synthesis

• Masashi Hasegawa,
• Junta Endo,
• Seiya Iwata,
• Toshiaki Shimasaki and
• Yasuhiro Mazaki

Beilstein J. Org. Chem. 2015, 11, 972–979, doi:10.3762/bjoc.11.109

• ; found: C, 51.36; H, 4.25. Synthesis of (R)/(S)-PTDPA: A mixture of Pd(OAc)2 (8.9 mg, 40 μmol), P(t-Bu)3·HBF4 (35 mg, 120 mmol), Cs2CO3 (290 mg, 2.8 mmol) in degassed NMP (1 mL) was stirred for 20 min at 100 °C under Ar atmosphere. Then, (R)-3 (80 mg, 151 μmol) and 4,5-bis(methylthio)TTF (67 mg, 226 μmol

• various types of aryl groups. At this point, we have chosen the direct arylation of TTF in the presence of a palladium catalyst as a key reaction for the chiral polymer synthesis (Scheme 2) [22]. Thus, the chiral allenes, (R)-9 or (S)-9, react with an active palladium species, prepared in situ from Pd(OAc

• )2 and P(t-Bu)3·HBF4 salt in the presence of CsCO3, to give the chiral copolymer of (R)-PTDPA and (S)-PTDPA, respectively, after purification by column chromatography on polystyrene Bio-beads. By using gel permeation chromatography (GPC), the number-average molecular weights (Mn) of the collected

An intramolecular C–N cross-coupling of β-enaminones: a simple and efficient way to precursors of some alkaloids of Galipea officinalis

• Hana Doušová,
• Radim Horák,
• Zdeňka Růžičková and
• Petr Šimůnek

Beilstein J. Org. Chem. 2015, 11, 884–892, doi:10.3762/bjoc.11.99

• over a substantially longer period (Table 1, entry 4). Buchwald et al. [47] described a protocol for generation of the highly active Pd(0) catalyst from Pd(OAc)2 using water-mediated pre-activation. However, no conversion was observed here for L1 (Table 1, entry 5). Besides palladium, copper is another

Weakly nucleophilic potassium aryltrifluoroborates in palladium-catalyzed Suzuki–Miyaura reactions: relative reactivity of K[4-RC₆F₄BF₃] and the role of silver-assistance in acceleration of transmetallation

• Vadim V. Bardin,
• Anton Yu. Shabalin and
• Nicolay Yu. Adonin

Beilstein J. Org. Chem. 2015, 11, 608–616, doi:10.3762/bjoc.11.68

• [C6F5BF3] retards toward K2CO3 [39] as well as K2CO3 in a mixture with catalytic amounts of Pd(OAc)2 in refluxing MeOH [19]. Resistance of K[C6F5BF3] (1a) towards K2CO3 and Ag2O in toluene (without palladium catalyst and phosphine ligand) is confirmed by stirring the corresponding suspensions at 100 °C for

Direct access to pyrido/pyrrolo[2,1-b]quinazolin-9(1H)-ones through silver-mediated intramolecular alkyne hydroamination reactions

• Hengshuai Wang,
• Shengchao Jiao,
• Kerong Chen,
• Xu Zhang,
• Linxiang Zhao,
• Dan Liu,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2015, 11, 416–424, doi:10.3762/bjoc.11.47

• ), mackinazolinone (4) and vasicinone (5) have been proven to act as bronchodilatory, anti-inflammatory, antimicrobial and antidepressant agents (Figure 1) [2][3][4][5][6][7][8]. A variety of approaches have been employed to synthesize deoxyvasicione (1) and its derivatives, e.g., the Pd(OAc)2-catalyzed carbonyl

Matsuda–Heck reaction with arenediazonium tosylates in water

• Ksenia V. Kutonova,
• Marina E. Trusova,
• Andrey V. Stankevich,
• Pavel S. Postnikov and
• Victor D. Filimonov

Beilstein J. Org. Chem. 2015, 11, 358–362, doi:10.3762/bjoc.11.41

• be effective catalysts for the Matsuda–Heck arylation of styrene and ethyl acrylate in water [7]. It is noteworthy that these catalysts are not commercially available and must be synthesized from Pd(OAc)2. Roglands et al. prepared a range of tert-butyl cinnamates and stilbenes from arenediazonium

• conditions. Methyl acrylate (1a) was chosen as a model substrate as it is highly reactive in standard Matsuda–Heck reactions. Therefore, a solution of 4-nitrobenzenediazonium tosylate (2a) in water was allowed to react with 1.2 equiv of methyl acrylate (1a) in the presence of 1 mol % Pd(OAc)2 at rt, at 75 °C

• heating [13]. Thus, the aim of our next experiment was the reduction of the reaction time by using microwave irradiation (Table 1, entry 3). By means of this protocol 3aa was obtained with an almost quantitative yield with a reaction time of only 1 min. Carrying out the reaction with 1 mol % of Pd(OAc)2

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• benzylideneaniline were subjected to the acetoxylation using the Pd(OAc)2/PhI(OAc)2 system [33]. More recently, reactions involving the same and some other directing groups were studied in more detail. In most of the studies, Pd(OAc)2 was used as the catalyst, and PhI(OAc)2 or peroxides served as the oxidants. The

• (II) complex is oxidized by silver(I) ions to Cu(III) complex 18, and the C–O bond is formed via reductive elimination. The drawbacks of this method are the use of large amounts of silver triflate and alcohol and the high temperature of the reaction. The Pd(OAc)2/persulfate system was used in the

• lower temperature (50 °C instead of 100 °C, as in the case of CH-reagents 22 and 23) [53]. The ortho-acetoxylation and methoxylation of O-methyl aryl oximes 31 with Pd(OAc)2 combined with such oxidants as oxone, potassium persulfate, and (diacetoxyiodo)benzene (Scheme 7, coupling products 32 and 33