Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• catalytic domino reactions. The group of Hayashi has reported in 2004 the first example of the transformation of a cyclic diaryl-λ3-iodane, for which both Ar–I bonds are used in a palladium cross-coupling reaction [56]. It relies on a double Heck reaction performed with methyl vinyl ketone in the presence

• –I motif (Scheme 22) [62]. Hence aryl- and alkyl-substituted terminal alkynes can be coupled via a Sonogashira reaction when PPh3 is used as ligand, while the use of diphenylphosphinoferrocenyl ligand (dppf) allows the Heck-type coupling of acrylates, vinyl ketones and electron-poor styrene

• , gives access to various iodoaminated intermediates that can be subsequently engaged in palladium-catalyzed Suzuki–Miyaura, Sonogashira, or Mizoroki–Heck cross-coupling reactions. Various aryl, alkenyl, or alkynyl substituents can thus be introduced in good to very good yields. When compared to the

Atom-economical group-transfer reactions with hypervalent iodine compounds

• Andreas Boelke,
• Peter Finkbeiner and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2018, 14, 1263–1280, doi:10.3762/bjoc.14.108

• iodoarenes 32. These species smoothly underwent subsequent Suzuki–Miyaura, Sonogashira and Mirozoki–Heck couplings. The respective arylated, alkynylated and alkenylated products 33a–d were obtained in high yields with excellent stereoselectivity. Due to the intramolecular pathway of the first step, high AE

• values (66% for 33b) are obtained. In another tandem procedure, a metal-free C(sp3)–H olefination of amidines 34 with DMSO and PIDA derivatives 20b was developed by Namitharan and co-workers [49]. A Pd(II)-catalysed Heck reaction of the formed exocyclic double bond with the emerging iodoarene yields

• then oxidized to the sulfoxide G by iodosoarene C via the postulated activated sulfoxide F, releasing one equivalent of aryl iodide 2. A Chugaev-type elimination yields the olefin H, which finally affords acrylamidine 35 via Heck coupling with the iodoarene 2 with 50% AE (for R1 = H, R2 = Bn, Ar1 = Ar2

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• benzotropylium ion 45. Secondly, 11 is obtained in 18% yield after benzylic bromination of 42 with NBS, followed by in situ elimination reaction of the labile bromide 43 mediated by t-BuOK (Scheme 9). Palladium-catalyzed C–C bond-formation reactions such as Heck and Sonogashira couplings are employed in a wide

• variety of areas in organic chemistry [56][57]. Recently, Shaabani’s group synthesized and characterized palladium nanoparticles supported on ethylenediamine-functionalized cellulose (PdNPs@EDACs) as a novel bio-supported catalyst for Heck and Sonogashira couplings in water [58]. Shaabani’s group reported

• the efficient synthesis of benzotropone 11 in a good isolated yield (83%) via PdNPs@EDACs-catalyzed Heck coupling and intramolecular condensation of 2-bromobenzaldehyde (46) and methyl vinyl ketone (47) (Scheme 10) [58]. 2.2. Reactions of 4,5-benzotropone (11) 2.2.1. Reactions via the carbonyl group

Bromide-assisted chemoselective Heck reaction of 3-bromoindazoles under high-speed ball-milling conditions: synthesis of axitinib

• Jingbo Yu,
• Zikun Hong,
• Xinjie Yang,
• Yu Jiang,
• Zhijiang Jiang and
• Weike Su

Beilstein J. Org. Chem. 2018, 14, 786–795, doi:10.3762/bjoc.14.66

• , PR China 10.3762/bjoc.14.66 Abstract A mechanically-activated chemoselective Heck coupling for the synthesis of 3-vinylindazoles has been developed with the aid of catalytic amounts of TBAB and NaBr as both dehalogenation restrainer and grinding auxiliary. After tuning of the chemical conditions and

• mechanical parameters, a series of non-activated 3-bromoindazoles and a broad scope of olefins worked well to give the corresponding coupling products in good to excellent yields. A further application of this protocol was performed in a two-step mechanochemical Heck/Migita cross coupling, which provided a

• highly efficient route for the synthesis of axitinib. Keywords: axitinib; ball-milling; dehalogenation; Heck reaction; indazoles; Introduction The palladium-catalyzed vinylation of alkenes in the presence of a base, known as the Heck reaction (Mizoroki–Heck reaction), is one of the most important

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• hydrophobic membrane and as a consequence a higher reaction rate. Dergunov et al. reported on the design of a porous polymeric nanoreactor with a lipid bilayer for coupling reactions [87]. These nanocapsules were loaded with palladium catalysts and successfully used in Suzuki, Sonogashira and Heck cross

Cobalt-catalyzed directed C–H alkenylation of pivalophenone N–H imine with alkenyl phosphates

• Wengang Xu and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2018, 14, 709–715, doi:10.3762/bjoc.14.60

• groups into the ortho position of functionalized arenes has attracted significant attention because of the synthetic versatility of alkenyl groups. The C–H alkenylation has been achieved most extensively by way of the dehydrogenative Heck-type reaction of olefins [7][8][9]. Meanwhile, the hydroarylation

• of alkynes has also been explored as an alternative approach for C–H alkenylation [10]. Despite the significant progress made, each of these C–H alkenylation manifolds has some critical limitations. For example, the dehydrogenative Heck reaction is often limited to activated monosubstituted alkenes

Diastereoselective auxiliary- and catalyst-controlled intramolecular aza-Michael reaction for the elaboration of enantioenriched 3-substituted isoindolinones. Application to the synthesis of a new pazinaclone analogue

• Romain Sallio,
• Stéphane Lebrun,
• Frédéric Capet,
• Francine Agbossou-Niedercorn,
• Christophe Michon and
• Eric Deniau

Beilstein J. Org. Chem. 2018, 14, 593–602, doi:10.3762/bjoc.14.46

• two steps sequence involving first a palladium-catalyzed Heck cross coupling between 2-bromobenzoic tert-butyl esters 9 and 10 with acrylamides 11a–e (69–72% isolated yields, Scheme 2, Figure 2). The subsequent removal of the t-butyl group in esters 12a–e and 13 (Figure 2) was then achieved by

• Scheme 5. Aldehyde 23 was first readily prepared via a Heck cross coupling reaction between 2-bromobenzaldehyde (22) and acrylamide 11f. Next, a Pinnick oxidation of the aldehyde 23 followed with a coupling reaction with chiral benzylamine 17 delivered the targeted benzamide 24 in good yield (65%). The

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• ]pyridines 32 and 34 (Scheme 5). In situ cyclocondensation of β-halovinyl aldehydes 29 with 5-aminopyrazoles (R = Ph, 16) under Heck conditions in the presence of Pd(OAc)2 with xantphos (4,5-bis(diphenylphosphino)-9,9-dimethylxanthene) gave 6-substituted pyrazolo[3,4-b]pyridines 34. On the other hand

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• different functional groups. But the reaction was sensitive to the steric hindrance of the olefin substrates, and 2-substituted terminal alkenes or internal (including cyclic) alkenes were not applicable to this protocol. A mechanistic study showed that the reaction may proceed through a Heck-like four

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• (CF3SO2)2Zn, which demonstrated great efficiency in introducing the CF3 moiety on (hetero)aromatic rings [34]. Trifluoromethylation of olefins: In 2005, Vogel and co-workers showed that terminal alkenes could be trifluoromethylated by means of CF3SO2Cl via a palladium-catalysed desulfitative Mizoroki–Heck

Palladium-catalyzed Heck-type reaction of secondary trifluoromethylated alkyl bromides

• Tao Fan,
• Wei-Dong Meng and
• Xingang Zhang

Beilstein J. Org. Chem. 2017, 13, 2610–2616, doi:10.3762/bjoc.13.258

• , Shanghai 200032, China 10.3762/bjoc.13.258 Abstract An efficient palladium-catalyzed Heck-type reaction of secondary trifluoromethylated alkyl bromides has been developed. The reaction proceeds under mild reaction conditions with high efficiency and excellent functional group tolerance, even towards

• formyl and hydroxy groups. Preliminary mechanistic studies reveal that a secondary trifluoromethylated alkyl radical is involved in the reaction. Keywords: alkenes; cross-coupling; Heck-type reaction; palladium; secondary trifluoromethylated alkyl bromides; Introduction With the increasing number of

• fluoroalkyl metal species [18][19][20][21][22][23][24]. Recently, we reported a palladium-catalyzed Heck-type reaction of fluoroalkyl bromides, representing an efficient and straightforward alternative to access fluoroalkylated alkenes [25][26][27]. Preliminary mechanistic studies reveal that a fluoroalkyl

Synthesis of substituted Z-styrenes by Hiyama-type coupling of oxasilacycloalkenes: application to the synthesis of a 1-benzoxocane

• James R. Vyvyan,
• Courtney A. Engles,
• Scott L. Bray,
• Erik D. Wold,
• Christopher L. Porter and
• Mikhail O. Konev

Beilstein J. Org. Chem. 2017, 13, 2122–2127, doi:10.3762/bjoc.13.209

• ; palladium; silicon; Introduction The development of transition metal-catalyzed cross-coupling technologies over the last four decades revolutionized the synthetic chemistry. Indeed, the importance of Pd-catalyzed coupling was recognized with the 2010 Nobel Prize awarded to Heck, Negishi and Suzuki [1][2

Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides

• Valentin A. Rassadin,
• Mirko Scholz,
• Anastasiia A. Klochkova,
• Armin de Meijere and
• Victor V. Sokolov

Beilstein J. Org. Chem. 2017, 13, 1932–1939, doi:10.3762/bjoc.13.187

• , sultams have been prepared employing Diels–Alder reactions, radical cyclizations, reductions of sulfonylimines, ring-closing metatheses, nucleophilic aromatic substitutions and Heck cyclizations [14][15][16]. Earlier on, our group has developed versatile syntheses of sultams based on the transformation of

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• % of PCy3·HBF4 along with an excess K2CO3–MeOH led to biaryls within 99 min and with a yield up to 97% (Scheme 8) [57]. Heck reaction Frejd and co-workers reported the first mechanochemical Heck reaction [58]. Su and co-workers demonstrated that (E)-stilbene derivatives were synthesized by the coupling

• . Easy purification procedures, towards quantitative conversion and minimum byproducts are additionally considered to be major significance to this method. Tullberg et al. investigated the Mizoroki–Heck reaction between iodobenzene and the methyl ester of N-Boc-protected aminoacylate under different

• ]. Mechanochemical Suzuki reaction [56]. Mechanochemical Suzuki–Miyaura coupling by LAG [57]. Mechanochemical Heck reaction [59]. a) Sonogashira coupling under milling conditions. b) The representative example of a double Sonogashira reaction of p-iodoacetophenone with 1,4-bis-ethynyl benzene. Copper-catalyzed CDC

Pd(OAc)₂/Ph₃P-catalyzed dimerization of isoprene and synthesis of monoterpenic heterocycles

• Dominik Kellner,
• Maximilian Weger,
• Andrea Gini and
• Olga García Mancheño

Beilstein J. Org. Chem. 2017, 13, 1807–1815, doi:10.3762/bjoc.13.175

• system PdBr2(dppe)/NaOPh/PhOH [31]. Furthermore, an interesting work by Heck and co-workers in 1976 already showed the possibility of generating the corresponding dimethyloctadienes of isoprene by a reductive dimerization in the presence of formic acid with the dimeric allylpalladium acetate catalyst and

An efficient Pd–NHC catalyst system in situ generated from Na₂PdCl₄ and PEG-functionalized imidazolium salts for Mizoroki–Heck reactions in water

• Nan Sun,
• Meng Chen,
• Liqun Jin,
• Wei Zhao,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 1735–1744, doi:10.3762/bjoc.13.168

• materials via a simple method. Their corresponding water soluble Pd–NHC catalysts, in situ generated from the imidazolium salts L1–L3 and Na2PdCl4 in water, showed impressive catalytic activity for aqueous Mizoroki–Heck reactions. The kinetic study revealed that the Pd catalyst derived from the imidazolium

• 10,000. Keywords: aqueous homogeneous catalysis; Mizoroki–Heck reaction; Na2PdCl4; PEG-functionalized imidazolium salts; Introduction Nowadays, both increasing environmental concerns and drastic commercial competition are the driving forces to develop more sustainable and economic processes for

• contributed to Suzuki–Miyaura reactions and only a very few examples were reported for Mizoroki–Heck reactions [45][51][53][57]. Previous research by Rösch and other groups disclosed that introducing a hemilable donor group (such as N, O, S etc.) on the NHC rings was favorable for the palladium-catalyzed

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• Mizoroki–Heck coupling reactions under microwave irradiation (MW) were carried out with a colloidal Pd nanocatalyst stabilized with poly(N-vinylpyrrolidone) (PVP). Many stilbenes and novel heterostilbenes were achieved in good to excellent yields starting from aryl bromides and different olefins. The

• make this protocol a great option for stilbene syntheses by Mizoroki–Heck reaction. Keywords: aqueous reaction medium; MAOS; Mizoroki–Heck reaction; Pd nanoparticle; sustainable organic synthesis; Introduction Palladium-catalyzed reactions have emerged as an important tool for organic synthesis

• both coupling partners. The Mizoroki–Heck reaction and related chemistry occupy a special place among the basic types of Pd-catalyzed reactions, particularly the vinylation of aryl/vinyl halides or triflates [7][8][9][10], explored not only in the inter- and intramolecular version [2][11][12][13], but

Encaging palladium(0) in layered double hydroxide: A sustainable catalyst for solvent-free and ligand-free Heck reaction in a ball mill

• Wei Shi,
• Jingbo Yu,
• Zhijiang Jiang,
• Qiaoling Shao and
• Weike Su

Beilstein J. Org. Chem. 2017, 13, 1661–1668, doi:10.3762/bjoc.13.160

• , Zhejiang, China 10.3762/bjoc.13.160 Abstract In this paper, the synthesis of a cheap, reusable and ligand-free Pd catalyst supported on MgAl layered double hydroxides (Pd/MgAl-LDHs) by co-precipitation and reduction methods is described. The catalyst was used in Heck reactions under high-speed ball

• milling (HSBM) conditions at room temperature. The effects of milling-ball size, milling-ball filling degree, reaction time, rotation speed and grinding auxiliary category, which would influence the yields of mechanochemical Heck reactions, were investigated in detail. The characterization results of XRD

• , ICP–MS and XPS suggest that Pd/MgAl-LDHs have excellent textural properties with zero-valence Pd on its layers. The reaction results indicate that the catalyst could be utilized in HSBM systems to afford a wide range of Heck coupling products in satisfactory yields. Furthermore, this catalyst could be

Total syntheses of the archazolids: an emerging class of novel anticancer drugs

• Stephan Scheeff and
• Dirk Menche

Beilstein J. Org. Chem. 2017, 13, 1085–1098, doi:10.3762/bjoc.13.108

• suitable olefination strategy. Subsequently, for connecting the resulting fragment to the thiazole subunit 6 a Heck reaction was envisioned as part of studies advancing this type of Palladium-catalyzed coupling strategies in complex target synthesis [61][62][63][64][65][66]. Finally, a HWE-macrocyclization

• synthesis, also on highly elaborate substrates. Considerable efforts were invested before the challenging Heck coupling with the thiazole fragment 6 could be effected with useful selectivities. Besides the desired E,E-diene 34 formation of other double bond isomers both in the southern and northern part of

• unambiguously confirming the stereochemistry of this macrolide [59]. Menche’s total synthesis of archazolid B One the methodological incentives of the synthetic campaign of the Menche group directed towards the archazolids were the further development and application of the Heck reaction in complex target

A strategic approach to [6,6]-bicyclic lactones: application towards the CD fragment of DHβE

• Tue Heesgaard Jepsen,
• Emil Glibstrup,
• François Crestey,
• Anders A. Jensen and
• Jesper Langgaard Kristensen

Beilstein J. Org. Chem. 2017, 13, 988–994, doi:10.3762/bjoc.13.98

• effective synthetic protocol to access [6,6]-bicyclic lactone moieties through a regio- and stereoselective intramolecular Mizoroki–Heck cross-coupling reaction followed by a 6π-electrocyclization. This method enabled the first synthesis of the elusive CD fragment of the Erythrina alkaloid DHβE. Preliminary

• pharmacological evaluations support the notion that the key pharmacophores of DHβE are located in the A and B rings. Keywords: DhβE; Mizoroki–Heck cross-coupling reaction; 6π-electrocyclization; [6,6]-bicyclic lactone; vinyl halide; Introduction The neuronal nicotinic acetylcholine receptors (nAChRs) have been

• intramolecular Mizoroki–Heck cross-coupling reaction and a 6π-electrocyclization as key steps. Results and Discussion First strategy with Ts and Cbz protecting groups As depicted in Scheme 1, our first strategy featured a late stage installation of the lactonic D ring by a 6π-electrocyclization and formation of

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• have applied a Heck-reduction–cyclization–alkylation (HRCA) methodology under mild and simple reaction conditions. First, diazonium salts 56 underwent the Heck reaction with methyl vinyl ketone (57) to give the cross-coupling products 58 followed by hydrogenation of the latter to give aromatic

Synthesis and optical properties of new 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles

• Anastasia S. Kostyuchenko,
• Tatyana Yu. Zheleznova,
• Anton J. Stasyuk,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2017, 13, 313–322, doi:10.3762/bjoc.13.34

• Discussion Synthetic toolbox It is well known that thiophenes containing acceptor groups such as CHO, CN or CO2Me at the C-2 position readily react with aryl halides in the presence of a Pd(II) catalyst through a Heck-type coupling [26]. We have synthesized the ethyl ester of 2,2'-bithiophene-5-carboxylic

Highly bulky and stable geometry-constrained iminopyridines: Synthesis, structure and application in Pd-catalyzed Suzuki coupling of aryl chlorides

• Yi Lai,
• Zhijian Zong,
• Yujie Tang,
• Weimin Mo,
• Nan Sun,
• Baoxiang Hu,
• Zhenlu Shen,
• Liqun Jin,
• Wen-hua Sun and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 213–221, doi:10.3762/bjoc.13.24

• showed a good catalytic efficiency for both Suzuki and Heck cross-coupling reactions. The favorable effect originated from the ring-fused framework being able to establish a strained environment for better stability. Efficient couplings were achieved with aryl bromides or iodides as substrates, however

Efficient access to β-vinylporphyrin derivatives via palladium cross coupling of β-bromoporphyrins with N-tosylhydrazones

• Vinicius R. Campos,
• Ana T. P. C. Gomes,
• Anna C. Cunha,
• Maria da Graça P. M. S. Neves,
• Vitor F. Ferreira and
• José A. S. Cavaleiro

Beilstein J. Org. Chem. 2017, 13, 195–202, doi:10.3762/bjoc.13.22

• , affording in such way important intermediates for different synthetic strategies [4][17][18]. There are methods available allowing the insertion of alkenyl groups into porphyrin macrocycles (e.g., Heck reaction [4], metathesis [7][19][20][21], Wittig reaction [22][23]). However, palladium-catalyzed cross

Poly(ethylene glycol)s as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins

• Andrea Mascitti,
• Massimiliano Lupacchini,
• Ruben Guerra,
• Ilya Taydakov,
• Lucia Tonucci,
• Nicola d’Alessandro,
• Frederic Lamaty,
• Jean Martinez and
• Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 19–25, doi:10.3762/bjoc.13.3

• other alternative energy inputs is still scarce. Only three examples highlight their peculiar role for metal-catalysed processes in a ball mill (Mirozoki–Heck reaction) [6], by ultrasound (copper-catalysed cyanation reaction) [7], and for co-crystal formation in the polymer-assisted grinding process