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

• Sanjay R. Borhade Suresh B. Waghmode Department of Chemistry, University of Pune, Ganeshkhind, Pune-411007, India 10.3762/bjoc.7.41 Abstract Palladium supported on nickel ferrite (Pd/NiF2O4) was found to be a highly active catalyst for the Suzuki coupling reaction between various aryl halides and

• Suzuki coupling reaction (Table 1). These results indicated that the reaction in polar aprotic solvents such as dimethylformamide (DMF), dimethylacetamide (DMA), N-methylpyrrolidin-2-one (NMP) and dimethylsulfoxide (DMSO) showed only 34–50% conversion after 2 h (Table 1, entries 1–4). The reaction in

• , 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

Conjugated polymers containing diketopyrrolopyrrole units in the main chain

• Bernd Tieke,
• A. Raman Rabindranath,
• Kai Zhang and
• Yu Zhu

Beilstein J. Org. Chem. 2010, 6, 830–845, doi:10.3762/bjoc.6.92

• -catalyzed Suzuki coupling was reported by Tieke and Beyerlein in 2000 [25]. The polymers contained N-hexyl-substituted diphenylDPP units and hexyl-substituted 1,4-phenylene units in the main chain and molecular weights of up to 21 kDa were determined. Compared with the monomer, the optical absorption of the

• ]. The polymers consisted of dialkylated DPP units and carbazole, triphenylamine, benzo[2,1,3]thiadiazole, anthracene, or fluorene units in alternating fashion. They were prepared via Suzuki coupling, from the DPP monomers M-1 or DPP-3,6-diphenyl(4,4´-bis(pinacolato)boron ester. A number of readily

• %) (see also Table 3). The nitrogen atoms in the backbone lower the band gap of the polymers to approximately 1.9 eV. The band gaps are lower than for the conjugated DPP-arene copolymers prepared upon Suzuki coupling [31] but higher than for the DPP-thiophene copolymers made by Stille coupling [36

Efficient and improved synthesis of Telmisartan

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

Beilstein J. Org. Chem. 2010, 6, No. 25, doi:10.3762/bjoc.6.25

• . This methodology overcomes many of drawbacks associated with previously reported syntheses. Keywords: antihypertensive drug; oxazoline hydrolysis; Suzuki coupling; Telmisartan; Introduction Telmisartan (1) is an angiotensin II receptor antagonist useful in the treatment of hypertension, heart

• starting materials for the preparation of the key biaryl intermediate. Thus, Suzuki coupling of 2-(2-bromophenyl)-4,4-dimethyl-2-oxazoline with 4-formylphenylboronic acid in presence of aqueous sodium carbonate and tetrakis(triphenylphosphine)palladium(0) in THF solvent gave 2’-(4,4-dimethyl-4,5-dihydro

Ring-alkyl connecting group effect on mesogenic properties of p-carborane derivatives and their hydrocarbon analogues

• Aleksandra Jankowiak,
• Piotr Kaszynski,
• William R. Tilford,
• Kiminori Ohta,
• Adam Januszko,
• Takashi Nagamine and
• Yasuyuki Endo

Beilstein J. Org. Chem. 2009, 5, No. 83, doi:10.3762/bjoc.5.83

• % yield from 1,4-dibromobenzene and (4-methoxyphenyl)boronic acid using the Suzuki coupling procedure [29]. This method is comparable to other Pd(0)-assisted methods for the synthesis of 14D[0] [30][31][32]. The 10-vertex p-carborane diester 18B was obtained from the corresponding dicarboxylic acid 22B

Ring strain and total syntheses of modified macrocycles of the isoplagiochin type

• Andreas Speicher,
• Timo Backes,
• Kerstin Hesidens and
• Jürgen Kolz

Beilstein J. Org. Chem. 2009, 5, No. 71, doi:10.3762/bjoc.5.71

• the syntheses of 3/4) should give rise only to the Z geometry at the a–d stilbene bridge. The a–b part 14 [15] of the target molecules was prepared by Suzuki coupling of the boronic acid 12 with its precursor 11, readily available from 3-bromo-4-methoxybenzaldehyde (10) [21] by an improved procedure

• and 26 were prepared as the “d” ring for Suzuki coupling with the bromoarene 16 (Scheme 5). First, iodination of 3-hydroxybenzoic acid (18) followed by double methylation and saponification of the methyl ester yielded 4-iodo-3-methoxybenzoic acid (19) which could be reduced in two steps [27] to the

• ] bromination lead to the formation of 2-bromo-5-methoxybenzyl alcohol, exclusively. Second, the triflate 24 was obtained from vanillin (23) and was further dioxane-protected at the aldehyde function (to 25) and directly transformed into the arylboronate 26 using pinacolborane [30]. Suzuki coupling of the

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

• demonstrates that we were able to utilise the functionalisation of bicyclic sulfonamide 5a featuring a Suzuki coupling and a diastereoselective hydrogenation to construct cis-2,4-diarylpyrrolidines in a diastereoselective manner. The epimerisation reaction which led to the formation of carboxylic acid 26

Studies on polynuclear furoquinones. Part 1: Synthesis of tri- and tetra- cyclic furoquinones simulating BCD/ABCD ring system of furoquinone diterpenoids

• Faruk H. Shaik and
• Gandhi K. Kar

Beilstein J. Org. Chem. 2009, 5, No. 47, doi:10.3762/bjoc.5.47

• 2-bromo-3,4-dihydro-1-naphthaldehyde. The bromoaldehyde was converted to methyl 2-(2-bromo-1-naphthyl)acetate or 2-(2-bromo-1-naphthyl)acetonitrile following the protocol of functional group transformations. Subsequent Suzuki coupling of this ester/nitrile derivative with furan-2-boronic acid

Preparation and Diels–Alder/cross coupling reactions of a 2-diethanolaminoboron- substituted 1,3-diene

• Liqiong Wang,
• Cynthia S. Day,
• Marcus W. Wright and
• Mark E. Welker

Beilstein J. Org. Chem. 2009, 5, No. 45, doi:10.3762/bjoc.5.45

• :1. Elemental anal. calcd. for C13H22BNO4: C, 58.45; H, 8.30. Found: 58.17, 8.32. Representative Suzuki coupling procedure General procedure: Boron compounds and iodoaromatic compounds were added to a N2 flushed flask with Pd2(dba)3 and K2CO3 in acetonitrile and ethanol (30 mL). The mixture was

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

• furnishing 4,5-dichloro-substituted compound 7a as a by-product in 13% yield. With the 4-halogenated 6H-1,2-oxazines 2 and 6 in hand, palladium-catalyzed cross couplings offer an efficient and useful approach for the synthesis of novel functionalized 6H-1,2-oxazines. The Suzuki-coupling of the 4-bromo

• , C-4), 122.7 (d, C-5), 148.5 (s, C-3), 160.3 (s, C=O) ppm. IR (neat): 3105–2975 (=C–H, C–H), 1745 (C=O), 1615 (C=N) cm−1. C9H12ClNO4 (233.7): calcd. C, 46.27; H, 5.18; N, 5.99; found: C, 46.35; H, 5.16; N, 6.08. Suzuki-coupling of 4-bromo-substituted 6H-1,2-oxazine 2a, typical procedure 6H-1,2

Regioselective alkynylation followed by Suzuki coupling of 2,4-dichloroquinoline: Synthesis of 2-alkynyl- 4-arylquinolines

• Ellanki A. Reddy,
• Aminul Islam,
• K. Mukkanti,
• Venkanna Bandameedi,
• Dipal R. Bhowmik and
• Manojit Pal

Beilstein J. Org. Chem. 2009, 5, No. 32, doi:10.3762/bjoc.5.32

• ) 10.3762/bjoc.5.32 Abstract A two step synthesis of 2-alkynyl-4-arylquinolines has been accomplished via Pd/C-mediated regioselective C-2 alkynylation of 2,4-dichloroquinoline in water followed by Suzuki coupling at C-4 of the resulting 4-chloro derivative. Keywords: alkyne; boronic acid; catalysis; 2,4

• -alkynyl-4-chloroquinoline (3) followed by successful Suzuki coupling at C-4 of compound 3 leading to the corresponding 4-arylated derivatives (5) in good yields (Scheme 1). To the best of our knowledge this is the first synthesis of 2-alkynyl-4-arylquinolines following such a strategy. Results and

• water to afford 2-alkynyl-4-chloroquinoline. The arylation step is a Pd-mediated (Suzuki) coupling of 2-alkynyl-4-chloro derivative with arylboronic acids in aqueous media to give the target compounds. The process is amenable to the diversity-oriented synthesis of quinoline derivatives of potential

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

• K3PO4 in acetonitrile at room temperature for 15 minutes. The same quantitative formation of the reduced arene was observed even in the absence of Pd catalyst. We therefore propose that Suzuki coupling between this and similar boronic acids is likely to be difficult under any conditions: alternative

• strategies are required. In summary, a readily prepared, air stable Pd pre-catalyst derived from the amine-phosphine ligand, dcpmp has been found to promote Suzuki coupling between activated aryl chlorides and a range of boronic acids under microwave heating conditions. High yields of the desired biaryls can