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

• ), while acrylamides having simple amine or amino acid moieties also participated in cross-coupling reactions with the arylurea to produce the corresponding amide derivatives in moderate to good yields (5s, 5t). Total synthesis of boscalid® via C–H activation The rationale behind the attention recently

• , affording the coupling product and Pd(0). The resulting Pd(0) is then oxidized with BQ to regenerate the dicationic palladium species, which can re-enter the catalytic cycle. Arylation with an aryl iodide. Coupling reactions of aryl iodides have fewer similarities in terms of traditional cross-coupling

Enantioselective carbenoid insertion into C(sp³)–H bonds

• J. V. Santiago and
• A. H. L. Machado

Beilstein J. Org. Chem. 2016, 12, 882–902, doi:10.3762/bjoc.12.87

• activation; chiral catalysis; diazo compounds; total synthesis; Introduction One of the major challenges met in organic synthesis is the formation of carbon–carbon bonds, in particular in a stereoselective way. Nucleophilic substitution reactions, radical reactions, cross-coupling reactions and the Heck

Bi- and trinuclear copper(I) complexes of 1,2,3-triazole-tethered NHC ligands: synthesis, structure, and catalytic properties

• Shaojin Gu,
• Jiehao Du,
• Jingjing Huang,
• Huan Xia,
• Ling Yang,
• Weilin Xu and
• Chunxin Lu

Beilstein J. Org. Chem. 2016, 12, 863–873, doi:10.3762/bjoc.12.85

• and platinum complexes containing 1,2,3-triazole-tethered NHC ligands. The obtained palladium complexes displayed high activity in aqueous Suzuki–Miyaura cross-coupling reactions. We are interested in the synthesis and use of functionalized NHC ligands [20][28][29][30][31]. Herein, the synthesis

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

• leading to a number of different 2,4- and 2,5-diaryldimethylpyridines P3, P4 [25], 4-benzylpyrimidines P2 [26], and 4-methyl-5-arylpyrimidines P1 [26] was needed. For this purpose, we successfully used Suzuki and Negishi cross-coupling reactions between arylboronic acids/benzylzinc reagents and

• /arylboronic acid ratio was gradually increased, also the increased presence of the dicoupled product was observed. However, the final separated yield decreased and most of the starting material could be recovered. Another important problem in sequential cross-coupling reactions is the proper choice of

Iridium/N-heterocyclic carbene-catalyzed C–H borylation of arenes by diisopropylaminoborane

• Mamoru Tobisu,
• Takuya Igarashi and
• Naoto Chatani

Beilstein J. Org. Chem. 2016, 12, 654–661, doi:10.3762/bjoc.12.65

• to introduce Suginome’s dan group, which allows us to use the borylated products in more elaborate manner, such as iterative cross-coupling reactions [20]. Conclusion We have developed a C–H borylation of arenes and heteroarenes using diisopropylaminoborane as a borylating reagent. An iridium(I

Synthesis and nucleophilic aromatic substitution of 3-fluoro-5-nitro-1-(pentafluorosulfanyl)benzene

• Javier Ajenjo,
• Martin Greenhall,
• Camillo Zarantonello and
• Petr Beier

Beilstein J. Org. Chem. 2016, 12, 192–197, doi:10.3762/bjoc.12.21

• -coupling reactions [25][26][27]. Synthetic methods to novel SF5-containing building blocks are sought after and drive the development of applications of these compounds. In this work, we explore SNAr chemistry of 3-fluoro-5-nitro-1-(pentafluorosulfanyl)benzene which was initially obtained as a minor

• , nitro(pentafluorosulfanyl)benzenes are widely-available primary industrial products and starting materials to other SF5-benzenes which were prepared by reduction followed by condensation or diazotization chemistry [8][14][15][16], SEAr [17], SNAr [18][19][20][21][22][23][24], or metal-catalyzed cross

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

• spectroscopic methods (1H and 13C{1H} NMR, UV–vis, ESI-FTICR-MS, FTIR) and elemental analysis. The PEPPSI Pd–NHC complexes were tested for catalytic activities both in direct arylation and Suzuki–Miyaura cross-coupling reactions. The catalytic activities of benzimidazolium salts were only tested in a Suzuki

• –NHC complexes as catalysts were studied in Suzuki–Miyaura cross-coupling reactions without an inert atmosphere. Both complex types were quite effective in the coupling of 4-chlorotoluene with 4-tert-butylphenylboronic acid. (A) UV–vis absorbance spectra were taken in DMSO. (B) The second derivative of

Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations

• Tsuyuka Sugiishi,
• Hideki Amii,
• Kohsuke Aikawa and
• Koichi Mikami

Beilstein J. Org. Chem. 2015, 11, 2661–2670, doi:10.3762/bjoc.11.286

• of CF3Cu, which participated in cross-coupling reactions with ArB(OH)2 in air [49]. Starting from CF3CO2Et or C2F5CO2Et, Mikami et al. obtained CF3Cu [44] or C2F5Cu [45]. The substrate scope of trifluoromethylation and pentafluoroethylation suggests that CF3Cu and C2F5Cu reagents are useful CnF2n+1

Versatile synthesis and biological evaluation of novel 3’-fluorinated purine nucleosides

• Hang Ren,
• Haoyun An,
• Paul J. Hatala,
• William C. Stevens Jr,
• Jingchao Tao and
• Baicheng He

Beilstein J. Org. Chem. 2015, 11, 2509–2520, doi:10.3762/bjoc.11.272

• ’-fluororibofuranose intermediate. Employing Suzuki and Stille cross-coupling reactions, fifteen 3’-fluororibose purine nucleosides 1–15 and eight 3’-fluororibose 2-chloro/2-aminopurine nucleosides 16–23 with various substituents at position 6 of the purine ring were efficiently synthesized. Furthermore, 3’-fluorine

• Stille and Suzuki cross-coupling reactions. 3’-Deoxy-3’-fluororibofuranosyl 2-chloropurine nucleosides 17–20 were synthesized by the similar strategy from the key intermediate 42. DME–water was found to be an efficient solvent system for Suzuki reaction on challenging substrates. De-chlorination of the 6

Comparison of the catalytic activity for the Suzuki–Miyaura reaction of (η⁵-Cp)Pd(IPr)Cl with (η³-cinnamyl)Pd(IPr)(Cl) and (η³-1-t-Bu-indenyl)Pd(IPr)(Cl)

• Patrick R. Melvin,
• Nilay Hazari,
• Hannah M. C. Lant,
• Ian L. Peczak and
• Hemali P. Shah

Beilstein J. Org. Chem. 2015, 11, 2476–2486, doi:10.3762/bjoc.11.269

• be closely related to cyclopentadienyl (Cp) ligands [17]. Nevertheless, to the best of our knowledge there are only two reports describing the catalytic activity of complexes of the type (η5-Cp)Pd(NHC)(Cl) for the Suzuki–Miyaura coupling, as well as related cross-coupling reactions [18][19]. These

Copper-catalyzed arylation of alkyl halides with arylaluminum reagents

• Bijay Shrestha and
• Ramesh Giri

Beilstein J. Org. Chem. 2015, 11, 2400–2407, doi:10.3762/bjoc.11.261

• excellent yields. Keywords: alkylation; arylalkanes; copper; cross-coupling; organoaluminum; Introduction Cross-coupling reactions represent one of the most important transformation for carbon–carbon (C–C) bond formation in organic synthesis [1][2][3][4][5][6][7][8][9]. These reactions, typically

• organoaluminum reagents could participate as nucleophile sources in Cu-catalyzed cross-coupling reactions. In this artcle, we show that triarylaluminum reagents are excellent coupling partners for Cu-catalyzed cross-coupling reactions. The reaction proceeds for the coupling with primary alkyl iodides and

Efficient synthetic protocols for the preparation of common N-heterocyclic carbene precursors

• Morgan Hans,
• Jan Lorkowski,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2015, 11, 2318–2325, doi:10.3762/bjoc.11.252

• imidazolylidene backbone in 1999 while searching for bulky NHC ligands to coordinate onto palladium catalysts for Kumada cross-coupling reactions [57]. The resulting carbene was nicknamed IPr and this designation still persists in the literature, although IDip is a more fitting acronym to avoid any confusion with

Cu(I)-catalyzed N,N’-diarylation of natural diamines and polyamines with aryl iodides

• Svetlana P. Panchenko,
• Alexei D. Averin,
• Maksim V. Anokhin,
• Olga A. Maloshitskaya and
• Irina P. Beletskaya

Beilstein J. Org. Chem. 2015, 11, 2297–2305, doi:10.3762/bjoc.11.250

• they were run at 110 °C. Normal catalytic loading was 5 mol % CuI and 10 mol % ligand per 1 amino group. At first we conducted the cross-coupling reactions between the simplest iodobenzene and diamines 1 and 2 to optimize the reaction conditions (Scheme 1, Table 1). As the resulting compounds 9–12 are

Recent developments in copper-catalyzed radical alkylations of electron-rich π-systems

• Kirk W. Shimkin and
• Donald A. Watson

Beilstein J. Org. Chem. 2015, 11, 2278–2288, doi:10.3762/bjoc.11.248

• radicals, these strategies have elegantly circumvented this problem and have expanded the scope of alkyl cross-coupling reactions. Nishikata has subsequently expanded the utility of this reaction manifold by elegant tailoring of the radical donor and acceptor [36]. If the styrene radical acceptor bears an

• potassium iodide, across alkynes to provide substituted vinyl iodides (Scheme 17) [40]. The process selectively forms the Z-alkenes. Although the E/Z ratios are often modest, the products are highly useful synthetic building blocks that may be used in subsequent cross-coupling reactions. The mechanism is

Copper catalysis in organic synthesis

• Sherry R. Chemler

Beilstein J. Org. Chem. 2015, 11, 2252–2253, doi:10.3762/bjoc.11.244

• been published in 2014. In point of fact, there has been a steady increase in publications on this topic since 1988. In the late 1980’s and early 1990’s, the topics centered on copper nitrene reactivity (e.g., aziridination), copper carbene chemistry, conjugate additions and cross-coupling reactions

• -coupling reactions were discovered over a century ago and their development has really blossomed over the past twenty years. Second, copper is an earth-abundant metal, making its use more cost effective and more sustainable than precious transition metal catalysts. Over 25 contributions from leaders in the

• . Depending on its oxidation state, this metal can efficiently catalyze reactions involving both one and two-electron (radical and polar) mechanisms, or both. Copper coordinates easily to heteroatoms and to π-bonds and is well-known to activate terminal alkynes. The Ullman and Goldberg C–C and C–N cross

Recent advances in copper-catalyzed C–H bond amidation

• Jie-Ping Wan and
• Yanfeng Jing

Beilstein J. Org. Chem. 2015, 11, 2209–2222, doi:10.3762/bjoc.11.240

• to give the corresponding quinoline derivatives 56 by simply treating 54 with PCl3 (Scheme 15). As another kind of conventional unsaturated hydrocarbons, the alkenes had been found to show similar reactivity with arenes in many cross coupling reactions. However, in the C–H amidation chemistry, the

Half-sandwich nickel(II) complexes bearing 1,3-di(cycloalkyl)imidazol-2-ylidene ligands

• Johnathon Yau,
• Kaarel E. Hunt,
• Laura McDougall,
• Alan R. Kennedy and
• David J. Nelson

Beilstein J. Org. Chem. 2015, 11, 2171–2178, doi:10.3762/bjoc.11.235

• . The new species were fully characterised using methods including NMR spectroscopy and X-ray crystallography. When tested in model Suzuki–Miyaura cross-coupling reactions, these complexes were found to be active for the cross-coupling of aryl bromides and aryl chlorides. Keywords: catalysis; cross

• NHC·HCl salt, rendering these species highly accessible (Scheme 1b) [10]. After the initial work by Cowley and Jones, various other researchers have disclosed complexes of this form and tested them in cross-coupling reactions such as Buchwald–Hartwig amination [11], Suzuki–Miyaura cross-coupling [12], and

• the shortest Cl–H distance being ca. 2.9 Å, approximately the sum of van der Waals radii of the two atoms. Assessment of catalytic activity With these new complexes in hand, their activity in some model cross-coupling reactions was examined. Ritleng and Chetcuti have deployed [Ni(Cp)(X)(NHC

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

• -coupling reactions are one of the most powerful technologies for the efficient synthesis of π-conjugated oligomers. As example, a π-conjugated thiophene triad incorporating a difluorinated phenylene unit has been previously synthesized in 60% yield using the Stille reaction of trimethyl(thiophen-2-yl

• oligomers have unique π-staking arrangement resulting sometimes in specific electronic properties [3]. Hence, a practical method for the synthesis of fluorinated π-conjugated oligomers that will use the specificity of fluorine atoms is highly desirable for the chemist community. Palladium-catalyzed cross

Aerobic addition of secondary phosphine oxides to vinyl sulfides: a shortcut to 1-hydroxy-2-(organosulfanyl)ethyl(diorganyl)phosphine oxides

• Svetlana F. Malysheva,
• Alexander V. Artem’ev,
• Nina K. Gusarova,
• Nataliya A. Belogorlova,
• Alexander I. Albanov,
• C. W. Liu and
• Boris A. Trofimov

Beilstein J. Org. Chem. 2015, 11, 1985–1990, doi:10.3762/bjoc.11.214

• -free conditions (15 vs 11 h). Meanwhile, this observation does not completely exclude a radical mechanism since the cross-coupling reactions between TEMPO and radical intermediates can be reversible [31]. In future, we intend to check various radical scavengers (other than TEMPO) in order to better

Influence of bulky yet flexible N-heterocyclic carbene ligands in gold catalysis

• Alba Collado,
• Scott R. Patrick,
• Danila Gasperini,
• Sebastien Meiries and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 1809–1814, doi:10.3762/bjoc.11.196

• -coupling reactions and other Pd-promoted transformations [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. The electronic and steric properties of the ITent family have been determined [21][42][45] and compared to the parent ligand IPr. The observed trend for both

• ][25][26], has been applied by a number of research groups to metal-catalysed transformations, leading to improvements in catalytic activity over other known systems [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. The ITent ligands have been successfully used in challenging Pd cross

SmI₂-mediated dimerization of indolylbutenones and synthesis of the myxobacterial natural product indiacen B

• Nils Marsch,
• Peter G. Jones and
• Thomas Lindel

Beilstein J. Org. Chem. 2015, 11, 1700–1706, doi:10.3762/bjoc.11.184

• ketone. Protection of the indole nitrogen was not necessary and 5 was obtained as a bright yellow solid in excellent yield (Scheme 1). The route appears more efficient than earlier procedures via 6-formylindoles [13][14][15]. There have been only few Pd-catalyzed cross-coupling reactions of unprotected 6

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

• -science [6][18][33][34][35][36][37][38], and material sciences [5][19][38][39] are emerging. Arylboronic acids and arylboronates represent versatile building blocks in organic synthesis [40]. They have found wide applications in transition metal-catalyzed cross-coupling reactions [41][42]. These boron

• -coupling reactions with varied degree of success. The most efficient cross-coupling reactions were the Heck reactions with alkenes, a biaryl homocoupling reaction, an azo coupling to electron-rich arenes, and a dediazoniation with TMSN3 in an ionic liquid medium [74][75]. An efficient borylation of

• . Starting from aniline derivative 1b, a one pot diazotization–borylation sequence using different acids afforded the corresponding borylated product 2b in good yields (Table 3). Suzuki–Miyaura cross-coupling reactions of boronates 2a and 2b with aryl iodides using a simple system without any optimization

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

• moiety), recently applied in the Morita–Baylis–Hillmann reaction [21]. The use of nitroxides in cross-coupling reactions is described only in a limited number of papers [22][23][24][25][26][27][28][29][30][31][32]. To the best of our knowledge, there are no systematic studies on the use of nitroxides in

Advances in the synthesis of functionalised pyrrolotetrathiafulvalenes

• Luke J. O’Driscoll,
• Sissel S. Andersen,
• Marta V. Solano,
• Dan Bendixen,
• Morten Jensen,
• Troels Duedal,
• Jess Lycoops,
• Cornelia van der Pol,
• Rebecca E. Sørensen,
• Karina R. Larsen,
• Kenneth Myntman,
• Christian Henriksen,
• Stinne W. Hansen and
• Jan O. Jeppesen

Beilstein J. Org. Chem. 2015, 11, 1112–1122, doi:10.3762/bjoc.11.125

• prepare BPTTFs using homocoupling reactions and functionalised MPTTFs using cross-coupling reactions with a variety of 1,3-dithiole-2-thiones (19). Subsequently, the incorporation of more complex functionality is discussed. We show how the 2-cyanoethyl protecting group can be used to afford MPTTFs

• published scale [25]. The equivalent reaction can be conducted using 7 to give BPTTF 5b with a similar yield of 79% [36], a modest improvement on the reported yield of 73% for the Boc-protected analogue [35]. The synthesis of MPTTFs can be achieved using cross-coupling reactions between 6 and 1,3-dithiole-2

• species [27]) can also be used in cross-coupling reactions, exemplified by its reaction with 19g to give 4g (Scheme 3 and Table 1) [36]. Our group has previously shown that it is also possible to introduce substituents directly onto the pyrrole ring of MPTTF 4d [40]. Further functionalisation of MPTTFs

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

• interesting for preparations on a larger scale. With the conditions chosen for the bromo derivatives, we turned our attention to the chloro derivatives. As chloro derivatives are more challenging substrates for cross-coupling reactions, we started with the successful catalytic system (Table 1, entry 3) but