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

• , internal alkenes (such as 39) were not affected during the reaction. Although the reaction proceeds via a distinct mechanism, the authors refer to the transformation as a formal Heck-type alkenylation of alkyl bromides. As with the nitroalkane alkylation chemistry illustrated above, this reaction is a rare

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

• -configuration were formed by SmI2-mediated reductive dimerization of a 4-(indol-6-yl)butenone, obtained by Heck reaction. The two indolyl units appear to chelate Sm(II)/(III) leading to a gauche-type arrangement at the newly formed bond between the two β-carbons. Through a sequence of Sonogashira cross coupling

• the crude material, 6-iodoindole was purified conveniently by sublimation in high vacuum affording a colorless product. The natural product (E)-4-(1H-indol-6-yl)but-3-en-2-one (5) isolated from Monodora angolensis [12] was obtained from 6-iodoindole (4) in one step via Heck reaction with methyl vinyl

• aliphatic side chain was introduced via N-isovaleroylpiperidine [36]. Removal of the TBS group by treatment with TBAF gave the natural product 20 in 47% yield as a colorless solid. Synthesis and biological activity of indiacen B The successful Heck reaction at unprotected 6-iodoindole prompted us to check

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

• -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

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

• -carbolinones have been developed [32][33][34][35][36], such as an intramolecular Heck reaction strategy of 2- and 3-iodoindoles for the synthesis of β- or γ-carbolinones by Beccalli et al. [32], AuCl3 and Pd-catalyzed cycloisomerization of indole-2-carboxamides to β-carbolinones [33][34][35], Pd-catalyzed

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

• Heck coupling: In 2003, Snieckus and co-workers [97] have synthesized the seco-C/D ring analogues of ergot alkaloids through the intramolecular Heck reaction as a key step. The coupling precursors 63 and 68 were prepared from 4-bromoindoles by a sequential Vilsmeier–Haack, Henry nitroaldol condensation

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

• Mizoroki–Heck cross-coupling reaction between 4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl and iodobenzene derivatives in the presence of palladium(II) acetate coordinated with a tri(o-tolyl)phosphine ligand immobilized in a polyurea matrix. Keywords: 4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1

• -oxyl; cinnamates; Mizoroki–Heck cross-coupling reaction; nitroxides; Introduction Cinnamic acid derivatives are known as biologically active compounds. Cinnamic acid and its hydroxy derivatives bearing a phenolic moiety such as coumaric, caffeic, ferulic, sinapinic, and chlorogenic acids [2][3][4][5

• been obtained using the Mizoroki–Heck cross-coupling reaction between aryl halides and an olefin [7][13][14][15][16][17]. Because cinnamates themselves are also olefins, they can serve as cinnamic substrates to synthesize more complex cinnamates [18][19]. Cinnamic acid derivatives are also formed when

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

• allylic alkylation of nucleophiles [30][31][32][33][34][35][36]. Some years ago, we synthesized the first example of Pd–benzothiazol-2-ylidene complex I (Figure 1), which proved to be an efficient catalyst for several C–C coupling reactions (like carbonylations and Heck olefinations) carried out in both

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

• Chemistry of New Materials NAS Belarus, 220141, Minsk, Belarus Department of General and Inorganic Chemistry, National Research Tomsk Polytechnic University, 634050 Tomsk, Russia 10.3762/bjoc.11.41 Abstract An environmentally friendly Matsuda–Heck reaction with arenediazonium tosylates has been developed

• ; diazonium salts; Matsuda–Heck reaction; microwave-assisted synthesis; stilbenes; Introduction Diazonium salts are known as one of the most valuable building blocks in organic synthesis [1]. Today, their most common use is the construction of carbon–carbon bonds in palladium-catalyzed reactions. Starting

• with the work of Matsuda’s group [2], who used a diazonium salt as a high-reactive electrophile for a Heck reaction, the Matsuda–Heck reaction does require the addition of neither bases nor ligands and is carried out under very mild conditions [3]. Furthermore, diazonium salts are more often prepared

Phosphinocyclodextrins as confining units for catalytic metal centres. Applications to carbon–carbon bond forming reactions

• Matthieu Jouffroy,
• Rafael Gramage-Doria,
• David Sémeril,
• Dominique Armspach,
• Dominique Matt,
• Werner Oberhauser and
• Loïc Toupet

Beilstein J. Org. Chem. 2014, 10, 2388–2405, doi:10.3762/bjoc.10.249

• -catalysed Mizoroki–Heck coupling reactions between aryl bromides and styrene on one hand, and the rhodium-catalysed asymmetric hydroformylation of styrene on the other hand. The inability of both chiral ligands to form standard bis(phosphine) complexes under catalytic conditions was established by high

• study dealing with the Mizoroki–Heck reactions, comparative tests were carried out with WIDEPHOS, a diphosphine analogue of HUGPHOS-2. Keywords: asymmetric hydroformylation; cyclodextrin; Heck reaction; homogeneous catalysis; palladium; phosphine; rhodium; Introduction Since the studies of Fu

• , Buchwald and Hartwig on the use of monophosphine ligands in cross-coupling reactions, notably carbon–carbon ones such as the Mizoroki–Heck [1][2][3] and Suzuki–Miyaura reactions [4][5][6], there is a renewed interest for tertiary phosphines that favour the formation of singly phosphorus-ligated complexes

Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications

• Mahesh K. Lakshman,
• Manish K. Singh,
• Mukesh Kumar,
• Raghu Ram Chamala,
• Vijayender R. Yedulla,
• Domenick Wagner,
• Evan Leung,
• Lijia Yang,
• Asha Matin and
• Sadia Ahmad

Beilstein J. Org. Chem. 2014, 10, 1919–1932, doi:10.3762/bjoc.10.200

• derivative under palladium-catalyzed conditions. The benzoyl ester of BtOH has been evaluated in a decarboxylative Pd-mediated Heck reaction, leading to a modest product yield [36]. However, this appears to be the only example of a BtOH derivative in Pd-mediated reactions. In principle, formation of π–allyl

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

• Thilo Focken and
• Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

Synthesis of rigid p-terphenyl-linked carbohydrate mimetics

• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 1749–1758, doi:10.3762/bjoc.10.182

• prepared p-bromophenyl-substituted bicyclic 1,2-oxazine derivatives 12, 13, 15 and 16 provide options to perform cross-coupling reactions such as Buchwald/Hartwig, Heck, Hiyama, Kumada, Sonogashira or Stille couplings. In order to examine the conditions for Suzuki cross-couplings we subjected bicyclic

C–H-Functionalization logic guides the synthesis of a carbacyclopamine analog

• Sebastian Rabe,
• Johann Moschner,
• Marina Bantzi,
• Philipp Heretsch and
• Athanassios Giannis

Beilstein J. Org. Chem. 2014, 10, 1564–1569, doi:10.3762/bjoc.10.161

• -dimethylaminopyridine, pyridine, 25 °C; then KOAc, MeOH, 64 °C, 85% yield for the two steps) to give 8. Generation of an enol triflate from the carbonyl group in 8 (potassium hexamethyldisilazide, phenyl bis-triflimide, THF, −20 → −10 °C, 85% yield) set stage for a Heck-reaction with methyl acrylate (cat. Pd(OAc)2, cat

Rational design of cyclopropane-based chiral PHOX ligands for intermolecular asymmetric Heck reaction

• Marina Rubina,
• William M. Sherrill,
• Alexey Yu. Barkov and
• Michael Rubin

Beilstein J. Org. Chem. 2014, 10, 1536–1548, doi:10.3762/bjoc.10.158

• Abstract A novel class of chiral phosphanyl-oxazoline (PHOX) ligands with a conformationally rigid cyclopropyl backbone was synthesized and tested in the intermolecular asymmetric Heck reaction. Mechanistic modelling and crystallographic studies were used to predict the optimal ligand structure and helped

• the isomerization were identified. It was shown that the nature of this isomerization is different from that demonstrated previously using chiral diphosphine ligands. Keywords: asymmetric catalysis; chiral phosphine ligands; cyclopropane; Heck reaction; organophosphorus; transition metal catalysis

• ; Introduction The asymmetric Heck reaction is one of the most powerful and versatile processes for the enantioselective construction of new carbon–carbon bonds. Intramolecular versions of this reaction catalysed by palladium complexes with BINAP and related diphosphine ligands [1][2] allow for efficient

On the mechanism of photocatalytic reactions with eosin Y

• Michal Majek,
• Fabiana Filace and
• Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2014, 10, 981–989, doi:10.3762/bjoc.10.97

• mechanistic pathways. Our experiments (Scheme 6) afforded quantum yields of Φ > 1 for the heterobiaryl coupling [15] and the Heck-type olefination with styrene [16], respectively. This indicates that in addition to a photocatalytic path (Scheme 2, A) radical-chain propagation is operating under the reaction

Visible light mediated intermolecular [3 + 2] annulation of cyclopropylanilines with alkynes

• Theresa H. Nguyen,
• Soumitra Maity and
• Nan Zheng

Beilstein J. Org. Chem. 2014, 10, 975–980, doi:10.3762/bjoc.10.96

• 21 in 52% yield. The fused indoline motif was formed via an intramolecular Heck reaction under Fu’s conditions [41] to provide a mixture of two olefinic regioisomers 22, which were converted to saturated fused indoline 23 under standard catalytic hydrogenation conditions in a combined yield of 40

Site-selective covalent functionalization at interior carbon atoms and on the rim of circumtrindene, a C₃₆H₁₂ open geodesic polyarene

• Hee Yeon Cho,
• Ronald B. M. Ansems and
• Lawrence T. Scott

Beilstein J. Org. Chem. 2014, 10, 956–968, doi:10.3762/bjoc.10.94

• (Heck-type cyclization), unfortunately, were unsuccessful. Heck-type cyclizations work nicely with planar PAHs and even on moderately curved PAHs, such as corannulene [15][23][24]. Nonetheless, when applied to the indenocircumtrindene synthesis, the reaction did not give any ring-closed products

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• desired DVCPR in almost quantitative yield at elevated temperature, followed by removal of the silyl-protecting group under acidic conditions to furnish cycloheptenone 70. Standard functional group interconversion furnished diolefin 71. Subjection of this compound to Heck coupling conditions resulted in

• in the formation of a bridged tetracycle after initial Heck coupling followed by carbo-palladation and subsequent β-hydride elimination [69][70][71]. Double bond regioisomers (between C7 & C8 or C13 & C14) were obtained. Oxidation with DDQ yielded the 1,6-unsaturated ketone 72. Selective epoxidation

Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

• Phei Li Lau,
• Ray W. K. Allen and
• Peter Styring

Beilstein J. Org. Chem. 2013, 9, 2886–2897, doi:10.3762/bjoc.9.325

• , 43500 Semenyih, Selangor Darul Shsan, Malaysia 10.3762/bjoc.9.325 Abstract The palladium metal catalysed Heck reaction of 4-iodoanisole with styrene or methyl acrylate has been studied in a continuous plug flow reactor (PFR) using supercritical carbon dioxide (scCO2) as the solvent, with THF and

• the reaction with methyl acrylate the reactor was scaled from a 1.0 mm to 3.9 mm internal diameter and the conversion and turnover frequency determined. The results show that the Heck reaction can be effectively performed in scCO2 under continuous flow conditions with a palladium metal, phosphine-free

• ; flow chemistry; Heck; palladium; supercritical carbon dioxide; Introduction The use of cross-coupling reactions between organometallic reagents and organic halides as a straightforward method of carbon–carbon bond formation has gained much popularity over the past three decades. The development of

Copper-catalyzed trifluoromethylation of alkenes with an electrophilic trifluoromethylating reagent

• Xiao-Ping Wang,
• Jin-Hong Lin,
• Cheng-Pan Zhang,
• Ji-Chang Xiao and
• Xing Zheng

Beilstein J. Org. Chem. 2013, 9, 2635–2640, doi:10.3762/bjoc.9.299

• reagents, it was proposed that the transformation might proceed via a radical, electrophilic or Heck-type process (Scheme 2) [47][48][49][50]. We reasoned that even if the reaction involved the radical process (path A, Scheme 2), the radical intermediate could still be oxidized to a cation because

• electrophilic trifluoromethylation reagents can be considered as an oxidant. In the presence of base, both of the cation and Heck-type intermediates should be able to undergo hydrogen elimination to form a Cvinyl–CF3 bond. On the basis of these reports and our hypothesis, we commenced to examine the reaction of

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• , and this simple procedure allowed for the functionalization of various N–H as well as variously N-protected indoles with almost complete selectivity for the 2-position, even in the case of “naked” indoles (Table 16). The same group also reported on two examples of Heck-type copper-catalyzed

Oxidative 3,3,3-trifluoropropylation of arylaldehydes

• Akari Ikeda,
• Masaaki Omote,
• Shiho Nomura,
• Miyuu Tanaka,
• Atsushi Tarui,
• Kazuyuki Sato and
• Akira Ando

Beilstein J. Org. Chem. 2013, 9, 2417–2421, doi:10.3762/bjoc.9.279

• aldehydes in the presence of fluoride anion [29]. Recently, Prakash et al. [30] reported the synthesis of β-trifluoromethylstyrenes through a Heck coupling reaction of aryl iodides with 1-iodo-3,3,3-trifluoropropane, allowing a direct introduction of 3,3,3-trifluoropropenyl groups to aromatic rings

Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

• Sudipta Pathak,
• Kamalesh Debnath and
• Animesh Pramanik

Beilstein J. Org. Chem. 2013, 9, 2344–2353, doi:10.3762/bjoc.9.269

• -catalyzed oxidative lactonization or an intramolecular cyclization reaction of δ-ketoaldehydes [12], a ruthenium-catalyzed aerobic oxidative cyclization of aromatic acids with alkynes [13], an FeCl3-promoted regioselective annulation of o-(1-alkynyl)benzoates with disulfides [14], a Heck–Matsuda cyclization

Flexible synthesis of anthracycline aglycone mimics via domino carbopalladation reactions

• Markus Leibeling and
• Daniel B. Werz

Beilstein J. Org. Chem. 2013, 9, 2194–2201, doi:10.3762/bjoc.9.258

• delivered the best results with yields of up to 89%. For the reaction mechanism we assume that the palladium(0) inserts into the C(sp2)–Br bond to form a Pd(II) species. A sequence of two carbopalladation reactions form a triene system which is able to cyclize by a Heck-type reaction, a 6π

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• step [84]. In 1996, Kurihara (Scheme 13) reported a [1,2]-Meisenheimer rearrangement followed by an intramolecular Heck cyclization to elaborate the isoindolobenzazocine moiety [85]. The synthesis commenced with the preparation of ester 106 from piperonal according to a known procedure [86]. A four

• chloride 110 gave 111, which upon sequential oxidation yielded enaminone 112. Finally, the isoindolinone moiety was generated via an intramolecular Heck reaction using tetrakis(triphenylphosphine)palladium(0) and thallium acetate, to give magallanesine (97) in excellent yield [85]. Aporphine alkaloids: The