Preparation of pyridine-3,4-diols, their crystal packing and their use as precursors for palladium-catalyzed cross-coupling reactions

• Tilman Lechel,
• Irene Brüdgam and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2010, 6, No. 42, doi:10.3762/bjoc.6.42

• possible palladium-catalyzed cross-couplings we performed several Sonogashira-reactions [28][29][30]. As described in Scheme 3, the pyridinyl-bistriflates or -nonaflates 3 were coupled with alkynes like phenylacetylene or (triisopropylsilyl)acetylene using Pd(PPh3)4 or alternatively, Pd(OAc)2/PPh3 as

• couplings of pyridinediyl bis(perfluoroalkanesulfonates) 3. a) Pd(PPh3)4 [or Pd(OAc)2/PPh3], CuI, iPr2NH, DMF, 70 °C, 4 h. b) TBAF, THF, rt, 1 h. Supporting Information Supporting Information File 1 contains the supplementary data for compounds 2d, 3a, 3c–d and 4b–c. Supporting Information File 90

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

• , THF, 70%; (c) n-BuLi, 25 °C, THF, anhyd ZnCl2, −20 °C, Q-phos, Pd(OAc)2, 75 °C, 2 h, 80%; (d) 3 N NaOH, MeOH, reflux, 90%. Acknowledgements We are grateful for the support of the Sardar Vallabhbhai National Institute of Technology, Surat and Indian Association for the Cultivation of Science, Jadavpur

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

• 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

• ; 5 mmol), phenylboronic acid (1; 6.19 mmol, 0.755 g, 124 mol %), Pd(OAc)2 (0.18 mmol, 0.04 g, 3.56 mol %) were added to the grinding beaker (agate, V = 45 ml) already equipped with the milling balls (6× agate, d = 15 mm) and placed inside the planetary ball mill Pulverisette 7 (Fritsch GmbH, Germany

• beakers (V = 45 ml), 6 agate milling balls (d = 15 mm) per beaker, 800 rpm, 10 min; batch: 5 mmol 2a, 124 mol % 1, 3.6 mol % Pd(OAc)2]. Results of the Suzuki–Miyaura reaction according to Scheme 1 assisted by pure aluminas [5 g SRS1–3: cf. Table 2; ball milling: 2 agate milling beakers (V = 45 ml), 6

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

• mixture of the compound 24a (500 mg, 1.75 mmol, 1 equiv), phenylboronic acid (1.073 g, 8.80 mmol, 5 equiv), Pd(OAc)2 (20 mg, 0.09 mmol, 5 mol %), PPh3 (47 mg, 0.18 mmol, 10 mol %) and Cs2CO3 (1.714 g, 5.26 mmol, 3 equiv) in a mixture of THF:H2O (10:1) (25 mL) was heated to reflux for 15 h. On cooling Et2O

Pd/C-mediated synthesis of α-pyrone fused with a five-membered nitrogen heteroaryl ring: A new route to pyrano[4,3-c]pyrazol-4(1H)-ones

• Dhilli Rao Gorja,
• Venkateswara Rao Batchu,
• Ashok Ettam and
• Manojit Pal

Beilstein J. Org. Chem. 2009, 5, No. 64, doi:10.3762/bjoc.5.64

• absence of PPh3 (Entry 3, Table 1). The use of other catalysts, e.g. PdCl2(PPh3)2, Pd(PPh3)4 or Pd(OAc)2-PPh3, afforded the product 3a in inferior yield (Entries 4-6, Table 1). Ethanol was found to be the best solvent in our study as the use of other solvents, e.g. 1,4-dioxane or DMF, decreased the

Palladium- catalyzed cross coupling reactions of 4-bromo- 6H-1,2-oxazines

• Reinhold Zimmer,
• Elmar Schmidt,
• Michal Andrä,
• Marcel-Antoine Duhs,
• Igor Linder and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2009, 5, No. 44, doi:10.3762/bjoc.5.44

• contrast, when the same reaction conditions were applied to the coupling of 2a and methyl propargyl ether, product 9d was obtained only in very low yield. In addition, Sonogashira coupling of 2a and methyl propargyl ether performed by an alternative protocol (Pd(OAc)2, CuI, PPh3, NHiPr2 in DMF) afforded

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

• ]. Parallel to our work, Chen, Yang and co-workers have independently developed a similar strategy for the synthesis of this type of heterocycle [22]. In their work, Chen and Yang demonstrated the importance of ligand structure on the outcome of the cyclization [optimized conditions: Pd(OAc)2, PCy3, K2CO3

• compounds that involved a CH-arylation step [DMSO, Pd(OAc)2, KOAc, 110 °C] afforded compound 1a in 58% yield (entry 1) [11][12]. Using other bases such as Ag2CO3, K3PO4 and Cs2CO3 under otherwise identical conditions gave inferior results (entries 2–4). Solvent played also an important role and among those

Shape- persistent macrocycle with intraannular alkyl groups: some structural limits of discotic liquid crystals with an inverted structure

• Sigurd Höger,
• Jill Weber,
• Andreas Leppert and
• Volker Enkelmann

Beilstein J. Org. Chem. 2008, 4, No. 1, doi:10.1186/1860-5397-4-1

• synthesis of the corresponding PAH building block and the subsequent macrocycle synthesis is displayed in Scheme 2. Treating the aromatic dibromo compound 10 with Pd(OAc)2 (20 mol%) and Cy2P(2,2′MeO)biph (30 mol%) in DMA gave the corresponding dibenzonaphthacene in 40-45% yield. Although a detailed

• of macrocycles with intraannular alkyl chains and extraannular PAH substituents. i) Pd(OAc)2, ligand, DBU, DMA (49%); BBr3, CH2Cl2 (99%); iii) I2/KI, ethylene diamine (quant.); iv) dimethyl sulfate, KOH, THF/water (50%); v) PdCl2(PPh3)2, CuI, piperidine/THF (71%); vi) Bu4NF, THF (97%); vii) CuCl

Synthesis of the Benzo- fused Indolizidine Alkaloid Mimics

• Daniel L. Comins and
• Kazuhiro Higuchi

Beilstein J. Org. Chem. 2007, 3, No. 42, doi:10.1186/1860-5397-3-42

• -dihydropyridones via palladium mediated cross-coupling and carboalkoxylation. [23] Initially, non-reductive Heck cyclization of 1l [24] was carried out in the presence of Pd(OAc)2 and AgNO3 in CH3CN. [22] Treatment of the product 11 with ICl in CH2Cl2 at 0°C gave the iodinated dihydropyridone 12 in 86% yield

Development of potential manufacturing routes for substituted thiophenes – Preparation of halogenated 2-thiophenecarboxylic acid derivatives as building blocks for a new family of 2,6-dihaloaryl 1,2,4-triazole insecticides

• John W. Hull Jr.,
• Duane R. Romer,
• David E. Podhorez,
• Mezzie L. Ash and
• Christine H. Brady

Beilstein J. Org. Chem. 2007, 3, No. 23, doi:10.1186/1860-5397-3-23

• -methylthiophene. Initial Bromination Approaches. Routes to 4-Bromo-3-methyl-2-thiopheneacid Chloride, 1, From 3-Methylthiophene, 4. (a) NBS/AcOH, 64%; (b) Pd(OAc)2/DPPP, Na2CO3, abs EtOH, 33 bar CO; or Mg turnings, THF, then dimethylcarbonate; (c) Br2/AcOH, NaOH; 60°C; then Zn dust, 85°C; (d) NaOH,/H2O, 91%; (e