Practical synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides via conventional and decarboxylative copper-free Sonogashira coupling reactions

• Andrea Caporale,
• Stefano Tartaggia,
• Andrea Castellin and
• Ottorino De Lucchi

Beilstein J. Org. Chem. 2014, 10, 384–393, doi:10.3762/bjoc.10.36

• bromides rather than expensive iodides and using 4 or propiolic acid rather than TMS-acetylene as inexpensive alkyne sources are described. Keywords: alkynes; decarboxylative couplings; Erlotinib; palladium; propiolic acid; Introduction The Sonogashira coupling reaction of aryl or alkenyl halides with

• ][11][12][13]. The Sonogashira coupling reaction is usually carried out under Pd/Cu catalysis, in which the palladium has the function to promote the cross-coupling of an aryl fragment, added via oxidative addition of the corresponding halide, with an alkynyl residue to provide a disubstituted

• of symmetrical and unsymmetrical diarylacetylenes resides not only in its low cost, but also in the possibility to carry out a conventional and a decarboxylative Sonogashira coupling reaction in sequence at the two sp carbons with two different aryl halides. Therefore a disubstituted alkyne can be

Total synthesis of the endogenous inflammation resolving lipid resolvin D2 using a common lynchpin

• John Li,
• May May Leong,
• Alastair Stewart and
• Mark A. Rizzacasa

Beilstein J. Org. Chem. 2013, 9, 2762–2766, doi:10.3762/bjoc.9.310

• . Desilylation of 11 followed by hydrozirconation and iodination gave the vinyl iodide 4 and Sonogashira coupling between this compound and enyne 3 provided alkyne 18. Acetonide deprotection, partial reduction and ester hydrolysis then gave resolvin D2 (1). Keywords: catalysis; eicosanoid; natural product

• ; resolvin D2; Sonogashira coupling; total synthesis; Wittig reaction; Introduction The resolution of inflammation is a tightly governed active process effectively mediated by a range of bioactive polyunsaturated fatty acids, peptides and proteins. In 2002, a new family of endogenously generated lipid

• can produce useful amounts of this important compound as well as novel isomers. Results and Discussion Retrosynthetic analysis A retrosynthetic analysis of RvD2 (1) is shown in Scheme 1. It was envisaged that the target compound 1 could be secured via a Sonogashira coupling to form the C11–C12 bond

Practical synthesis of indoles and benzofurans in water using a heterogeneous bimetallic catalyst

• Cybille Rossy,
• Eric Fouquet and
• François-Xavier Felpin

Beilstein J. Org. Chem. 2013, 9, 1426–1431, doi:10.3762/bjoc.9.160

• efficiency of our catalytic system highlighting the role of water in solvating the substrates. We then evaluated the influence of the nitrogen protecting group for the cascade Sonogashira coupling–cyclization sequence on two model reactions (Scheme 2). We observed that the coupling of phenyl acetylene (2

Some aspects of radical chemistry in the assembly of complex molecular architectures

• Béatrice Quiclet-Sire and
• Samir Z. Zard

Beilstein J. Org. Chem. 2013, 9, 557–576, doi:10.3762/bjoc.9.61

• starting xanthate. For instance, a regioselective Sonogashira coupling leading to compound 57 may be performed without affecting the less reactive chlorine substituent. The annelation commencing with xanthate 58 and furnishing indole derivative 59, an advanced intermediate in the formal synthesis of

Asymmetric total synthesis of smyrindiol employing an organocatalytic aldol key step

• Dieter Enders,
• Jeanne Fronert,
• Tom Bisschops and
• Florian Boeck

Beilstein J. Org. Chem. 2012, 8, 1112–1117, doi:10.3762/bjoc.8.123

• an acetonide, whereupon lactonization would take place simultaneously. Alkyne 5 could be synthesized through a Sonogashira coupling with iodide 6. This acetonide could be formed by addition of a methyl anion equivalent to the carbonyl group of the aldol product 7 with subsequent protection of the 1,3

On the bromination of the dihydroazulene/vinylheptafulvene photo-/thermoswitch

• Virginia Mazzanti,
• Martina Cacciarini,
• Søren L. Broman,
• Christian R. Parker,
• Magnus Schau-Magnussen,
• Andrew D. Bond and
• Mogens B. Nielsen

Beilstein J. Org. Chem. 2012, 8, 958–966, doi:10.3762/bjoc.8.108

• optical and redox properties [13]. The two bromo positions of 14 showed very different reactivity. Thus, subjecting 14 to a Sonogashira coupling with triisopropylsilylacetylene by using the Pd(PPh3)2Cl2/CuI catalyst system only gave the monocoupled product 15 (Scheme 7), confirmed by X-ray crystal

Diarylethene-modified nucleotides for switching optical properties in DNA

• Sebastian Barrois and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2012, 8, 905–914, doi:10.3762/bjoc.8.103

• last two synthetic steps are similar to those for nucleoside 4. Deprotection of 12 gave the doubly ethinylated diarylethene 15 in quantitative yield. The subsequent Sonogashira coupling with 14 at rt gave the mono-nucleosidic product 5 in 23% yield, and at 60 °C the di-nucleosidic product 6 in 35

Branching out at C-2 of septanosides. Synthesis of 2-deoxy-2-C-alkyl/aryl septanosides from a bromo-oxepine

• Supriya Dey and
• Narayanaswamy Jayaraman

Beilstein J. Org. Chem. 2012, 8, 522–527, doi:10.3762/bjoc.8.59

• acceptor moieties in C–C bond forming Heck, Suzuki and Sonogashira coupling reactions, thus affording 2-deoxy-2-C-alkyl/aryl septanosides. Whereas Heck and Sonogashira coupling reactions afforded 2-deoxy-2-C-alkenyl and -alkynyl derivatives, respectively, the Suzuki reaction afforded 2-deoxy-2-C-aryl

• , Heck, Suzuki and Sonogashira coupling reactions. Heck coupling reactions [24][25] were undertaken first. Thus, the reaction of bromo-oxepine 2 with methyl acrylate was performed, in the presence of Pd(OAc)2 (10 mol %) and Cs2CO3 in 1,4-dioxane, at 98 °C (Scheme 1), to afford diene 3, in 70% yield. The

• bromo-oxepine 2, efforts were undertaken to implement C–C bond forming Suzuki and Sonogashira coupling reactions. Suzuki reactions were undertaken by involving phenylboronic acid and substituted phenylboronic acids [26][27], in the presence of Pd(OAc)2 (10 mol %) and Cs2CO3 in 1,4-dioxane at 98 °C

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

• wheel precursors. Keywords: multivalency; pseudorotaxanes; Sonogashira coupling; supramolecular chemistry; tetralactam macrocycles; Introduction Synthetic supramolecular complexes have the great potential to put those concepts to the test that govern much of the noncovalent chemistry in nature. Among

• " of multivalent host and guest molecules has been described, which can be obtained from the two easy-to-prepare building blocks 1 and 2 by Sonogashira coupling reactions to ethynyl-substituted spacers. This synthetic approach is convergent, and thus the sometimes limited yields do not detract from

• Sonogashira coupling to the appropriate spacers: (a) EDC, HOBt, DMF, 22 h, 92%; (b) H2, Pd/C, EtOH, 3 d, 98%; (c) EDC.HCl, HOBt, DMF, 24 h, 73%; (d) I2, PIDA, AcOH/Ac2O, 1 h, 67%; (EDC = 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, HOBt = 1-hydroxybenzotriazole, DMF = N,N'-dimethylformamide, PIDA

Pseudo five-component synthesis of 2,5-di(hetero)arylthiophenes via a one-pot Sonogashira–Glaser cyclization sequence

• Dominik Urselmann,
• Dragutin Antovic and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1499–1503, doi:10.3762/bjoc.7.174

• . Deviating from the general procedure, in the case of m-bromo-iodobenzene (1d) only 1 equiv of TMSA was added in order to minimize a second alkynylation at the bromine position in the initial Sonogashira coupling step, which resulted in a moderate yield of the dibromo derivative (2d). Upon reaction of the m

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

• reported by Wu and coworkers. Initial Sonogashira coupling was effected between a 2-bromobenzaldehyde and an alkyne in the presence of catalytic amounts of PdCl2(PPh3)2 and CuI. After complete conversion of the aldehyde into the coupling product 25 (TLC control), a primary amine and diethylphosphite were

• ynones were then treated in situ with sodium iodide and PTSA to yield 2-substituted N-Boc-4-iodopyrroles 32 in good overall yields. Interestingly, this product may be further transformed in situ into the corresponding N-Boc-4-alkynylpyrroles 33 by a further Sonogashira coupling that makes use of the

• -step reaction with, first, a Sonogashira coupling of o-haloanilines with terminal alkynes, followed by a cyclization reaction of the resulting 2-alkynyaniline derivatives [26][27]. A strategy for the preparation of indoles through a three-component reaction consisted of generating the terminal alkyne

Combined directed ortho-zincation and palladium-catalyzed strategies: Synthesis of 4,n-dimethoxy-substituted benzo[b]furans

• Verónica Guilarte,
• M. Pilar Castroviejo,
• Estela Álvarez and
• Roberto Sanz

Beilstein J. Org. Chem. 2011, 7, 1255–1260, doi:10.3762/bjoc.7.146

• benzo[b]furan derivatives has been developed from 3-halo-2-iodoanisoles bearing an additional methoxy group, which have been accessed through an ortho-zincation/iodination reaction. Two palladium-catalyzed processes, namely a Sonogashira coupling followed by a tandem hydroxylation/cyclization sequence

• ring system, the cyclodehydration of α-aryloxy ketones [29], the Claisen rearrangement of an allyl aryl ether followed by Pd-catalyzed intramolecular oxidative cyclization [30], and the tandem Sonogashira coupling/heterocyclization of 2-halophenols with terminal alkynes [31], are some of the most used

• Sonogashira coupling and a tandem hydroxylation/heterocyclization reaction. The required o-dihaloanisole derivatives could be prepared by a selective ortho-metallation reaction and subsequent electrophilic quenching with iodine (Scheme 1). Results and Discussion As established in our proposed retrosynthetic

One-pot four-component synthesis of pyrimidyl and pyrazolyl substituted azulenes by glyoxylation–decarbonylative alkynylation–cyclocondensation sequences

• Charlotte F. Gers,
• Julia Rosellen,
• Eugen Merkul and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1173–1181, doi:10.3762/bjoc.7.136

• one-pot four-component syntheses toward pyrimidyl- and pyrazolylazulenes. Results and Discussion Recently, we reported a three-component synthesis leading to the formation of ynones by a conceptually novel glyoxylation–decarbonylative Sonogashira coupling sequence (Scheme 2) [47]. The Lewis acid free

• glyoxylation of electron rich N-heterocycles, such as indoles and pyrroles, leads to the formation of glyoxylyl chlorides, which can be reacted without isolation by decarbonylative Sonogashira coupling to form the desired ynones. So far, only one example of the synthesis of azulenylynones has been described

• monitoring by TLC, glyoxylation of guaiazulene (1b) was incomplete even after 24 h reaction time (Table 1, entry 3). Shorter reaction times in the first step caused a substantial decrease of the yield (Table 1, entry 4), whereas longer reaction times in the Sonogashira coupling had no effect on the yield

Fine-tuning alkyne cycloadditions: Insights into photochemistry responsible for the double-strand DNA cleavage via structural perturbations in diaryl alkyne conjugates

• Wang-Yong Yang,
• Samantha A. Marrone,
• Nalisha Minors,
• Diego A. R. Zorio and
• Igor V. Alabugin

Beilstein J. Org. Chem. 2011, 7, 813–823, doi:10.3762/bjoc.7.93

• corresponding lysine conjugates shown in Figure 4. Results and Discussion Synthesis The regioisomeric diaryl alkynes were synthesized following the synthetic strategy previously outlined by us for compound 1 [25]. The Sonogashira coupling of the corresponding iodonitrobenzene with trimethylsilyl (TMS) acetylene

C–C (alkynylation) vs C–O (ether) bond formation under Pd/C–Cu catalysis: synthesis and pharmacological evaluation of 4-alkynylthieno[2,3-d]pyrimidines

• Dhilli Rao Gorja,
• K. Shiva Kumar,
• K. Mukkanti and
• Manojit Pal

Beilstein J. Org. Chem. 2011, 7, 338–345, doi:10.3762/bjoc.7.44

• ]pyrimidines C (Figure 1). These derivatives are attractive due to the synthetic potential of C-4 alkynyl fragments for further use in library construction. A number of methods have been reported for the synthesis of alkynyl substituted pyrimidines and most of which involve the use of Sonogashira coupling of

• ]. The use of Pd/C–CuI–PPh3 as a less expensive catalyst system for efficient Sonogashira coupling has been explored earlier. Due to our continuing interest in Pd/C-mediated alkynylation of aryl and heteroaryl halides we decided to investigate the Pd/C-based methodology for the synthesis of our target

First synthesis of 2-(benzofuran-2-yl)-6,7-methylene dioxyquinoline-3-carboxylic acid derivatives

• Wentao Gao,
• Jia Liu,
• Yun Jiang and
• Yang Li

Beilstein J. Org. Chem. 2011, 7, 210–217, doi:10.3762/bjoc.7.28

• construction of the benzofuran moiety from intermediate 5. For the construction of 2-substituted benzofurans, the most widely used approach involves the palladium-catalyzed heteroannulation of 2-halophenols with a terminal alkyne via a tandem Sonogashira coupling-5-endo-dig-cyclization, largely based on the

Donor-acceptor substituted phenylethynyltriphenylenes – excited state intramolecular charge transfer, solvatochromic absorption and fluorescence emission

• Ritesh Nandy and
• Sethuraman Sankararaman

Beilstein J. Org. Chem. 2010, 6, 992–1001, doi:10.3762/bjoc.6.112

• (2) with 1,1-dimethylpropargyl alcohol followed by deprotection with KOH in refluxing toluene (Scheme 2). 2-Phenylethynyltriphenylene (1a) and those bearing electron withdrawing substituent (1b–e) were synthesized by the Sonogashira coupling of 2-iodotriphenylene (2) with the corresponding

• phenylacetylene derivatives. Although 1f–g were also synthesized by this procedure, their purification proved difficult due to an inseparable minor product formed in these reactions. Therefore compounds 1f–g were synthesized via the Sonogashira coupling of 2-ethynyltriphenylene (4) and the corresponding

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

• polycondensation reactions such as Suzuki [17], Stille [18] and Heck [19] coupling are especially useful. Other suitable reactions are Ni-mediated Yamamoto coupling [20], Sonogashira coupling [21], or electrochemical polymerization [22]. In the following, a brief review of recently prepared DPP based polymers is

• -sensitized solar cells were fabricated with P-12 as active layer. A power conversion efficiency of 1.43% was reached. G. Zhang et al. [52] synthesized diphenylDPP-containing polyphenylene-vinylene (PPV)- and polyphenylene-ethynylene (PPE)-type conjugated polymers via Heck- and Sonogashira coupling

• Suzuki coupling and their characteristic properties. List of DPP-polymers prepared upon Stille, Heck and Sonogashira coupling and their characteristic properties. List of DPP-based polyiminoarylenes and their characteristic properties [37]. List of DPP-polymers prepared upon electrochemical

One-pot three-component synthesis of quinoxaline and phenazine ring systems using Fischer carbene complexes

• Priyabrata Roy and
• Binay Krishna Ghorai

Beilstein J. Org. Chem. 2010, 6, No. 52, doi:10.3762/bjoc.6.52

• ] using palladium catalyzed Sonogashira coupling reactions as depicted in Scheme 2. Iodoketone 6A was prepared in 80% yield from (3-chloro-2-pyrazinyl)phenylmethanone [35] by halogen exchange with NaI in acetonitrile. The three component coupling reaction of pyrazinyl ketone 1A, carbene complex 2 and N

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

• (C-H), 1600–1575 (C=C) cm−1. C12H10F9NO6S2 (499.3): calcd. C, 28.86; H, 2.02; N, 2.81; found: C, 28.89; H, 1.68; N 2.87. Sonogashira coupling reaction, typical procedure A mixture of pyridinediyl bistriflate 3b (245 mg, 0.491 mmol), Pd(PPh3)4 (79 mg, 0.069 mmol), CuI (9.4 mg, 0.049 mmol

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

• single product in 65% yield. When the Sonogashira coupling was performed with trimethylsilylethyne under the same reaction conditions an inseparable 85:15-mixture of mono-alkynylated product 10b and bis-alkynylated compound 11b was obtained in reasonable yield. These reactions certainly deserve further

• , Ph, C-4), 157.7 (s, C-3) ppm. IR (KBr): 3040–2930 (=C–H, C–H), 1620 (C=N), 1600 (C=C) cm−1. C18H17NO2 (279.3): calcd. C, 77.39; H, 6.13; N, 5.01; found: C, 77.82; H, 6.37; N, 5.08. Sonogashira-coupling of 4-bromo-substituted 6H-1,2-oxazine 2a, typical procedure 6H-1,2-Oxazine 2a (0.850 g, 3.19 mmol

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

• . (a) arylation at C-4 followed by alkynylation at C-2 or (b) alkynylation at C-2 followed by arylation at C-4. Methodologies based on strategy ‘a’ have been reported earlier. For example, Sonogashira coupling of a terminal alkyne with 2-chloro-4-aryl substituted quinoline [3] in the presence of (PPh3

• singlet at δ 8.03 assigned to the C-3 hydrogen of the quinoline ring. If the alkyne was at C-4, NOE enhancement at C-5 is expected in addition to C-3. It is note worthy that the use of the Sonogashira coupling or its modified form has been employed for the preparation of 2-alkynylquinolines or related

Synthesis of novel photochromic pyrans via palladium- mediated reactions

• Christoph Böttcher,
• Gehad Zeyat,
• Saleh A. Ahmed,
• Elisabeth Irran,
• Thorben Cordes,
• Cord Elsner,
• Wolfgang Zinth and
• Karola Rueck-Braun

Beilstein J. Org. Chem. 2009, 5, No. 25, doi:10.3762/bjoc.5.25

• transformations. Synthesis of the 2-bromo-3H-naphtho[2,1-b]pyran 1 and the 3-bromo-2H-1-benzopyrans 2a/b. Ring contraction observed during the cyanation approach towards the synthesis of 3. Palladium-catalyzed Sonogashira-coupling of 2-bromo-3H-naphtho[2,1-b]pyran 1. Palladium-catalyzed cyanation 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

• . Overall 12 extended π-linkers have been easily synthesized (8 of them are new compounds) utilizing procedures such as a lithiation/reaction with triisopropyl borate/esterification with pinacol, Mizoroki–Heck coupling with vinylboronate pinacol ester, borylation with bis(pinacolato)diboron or Sonogashira

• coupling. Further application of the above boronic esters as well as terminal acetylenes for the construction of imidazole-based D-π-A systems by Suzuki–Miyaura and Sonogashira reaction is currently in progress in our laboratory. Basic and newly proposed π-conjugated linkers designed for the Suzuki–Miyaura

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

• constructed with excellent stereoselectivity by asymmetric alkynylation of α-tetrahydrofuranic aldehyde 114 with 1,6-heptadiyne (115). Then Sonogashira coupling of 116 and the iodide 117 followed by hydrogenation and deprotection provided murisolin (111). The spectroscopic data of synthetic 111 (1H NMR, 13C