A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations

• Thines Kanagasundaram,
• Antje Timmermann,
• Carsten S. Kramer and
• Klaus Kopka

Beilstein J. Org. Chem. 2019, 15, 2569–2576, doi:10.3762/bjoc.15.250

• catalyst, different substituted boroxines were assessed to explore the scope of the Pd-catalyzed cross-coupling reaction. Conclusions: A number of silicon rhodamines were synthesized under the optimized conditions in up to 91% yield without the necessity of HPLC purification. Moreover, silicon rhodamines

• –11b (Scheme 2) [22][28]. Hereby, the boroxines 9b–11b were accessible by thermal dehydration of the corresponding boronic acids 9a–11a. With this procedure product 13 was obtained in only 6% yield, which is presumably due to a competing coupling reaction of the boroxine moiety of 9b with the chlorine

• atom of 9b or sterical reasons (the chlorine in 2’-position might lead to repulsion during the cross-coupling reaction). The reaction of the triflate with cyano-substituted phenylboroxines 10b and 11b led to silicon rhodamine dyes 14 and 15 in poor yields of 23 and 19%, respectively. The reaction

Self-assembled coordination thioether silver(I) macrocyclic complexes for homogeneous catalysis

• Zhen Cao,
• Aline Lacoudre,
• Cybille Rossy and
• Brigitte Bibal

Beilstein J. Org. Chem. 2019, 15, 2465–2472, doi:10.3762/bjoc.15.239

• reactions of alkynes. Results and Discussion Synthesis of silver(I) complexes Ligand 1 was synthesized in one step, from commercially available 9,10-dibromoanthracene and 2-(methylthio)phenylboronic acid, using a Suzuki–Miyaura cross-coupling reaction. Notably, the yield was low (26%) [55], and the X-ray

Sugar-derived oxazolone pseudotetrapeptide as γ-turn inducer and anion-selective transporter

• Sachin S. Burade,
• Sushil V. Pawar,
• Tanmoy Saha,
• Navanath Kumbhar,
• Amol S. Kotmale,
• Manzoor Ahmad,
• Pinaki Talukdar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2019, 15, 2419–2427, doi:10.3762/bjoc.15.234

• converted to amino acid di- and tetrapeptides 8 and 9, respectively, using hydrolysis followed by a hydrogenation reaction protocol (Scheme 2). In order to get cyclic peptides I and II (Figure 1), an individual intramolecular coupling reaction of linear dipeptide 8 and tetrapeptide 9 was attempted. Thus

• functionalities are apart from each other. However, an individual intramolecular coupling reaction of 8 and 9 using CMPI as a coupling reagent, in the presence of Et3N in dichloromethane, afforded pseudodipeptide 1 and pseudotetrapeptide 2a, respectively, with oxazolone ring formation at the C-terminal of the

Functionalization of 4-bromobenzo[c][2,7]naphthyridine via regioselective direct ring metalation. A novel approach to analogues of pyridoacridine alkaloids

• Benedikt C. Melzer,
• Alois Plodek and
• Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2304–2310, doi:10.3762/bjoc.15.222

• ]. Reaction of allyl iodide (17) with metalated 9d after addition of catalytic amounts of CuCN∙2LiCl led to the formation of the 5-allyl compound 18 in 37% yield. Metalation of 9d using TMPMgCl∙LiCl and subsequent transmetalation with ZnCl2 followed by Negishi cross-coupling reaction in the presence of Pd(dba

Aggregation-induced emission effect on turn-off fluorescent switching of a photochromic diarylethene

• Luna Kono,
• Yuma Nakagawa,
• Ayako Fujimoto,
• Ryo Nishimura,
• Yohei Hattori,
• Toshiki Mutai,
• Nobuhiro Yasuda,
• Kenichi Koizumi,
• Satoshi Yokojima,
• Shinichiro Nakamura and
• Kingo Uchida

Beilstein J. Org. Chem. 2019, 15, 2204–2212, doi:10.3762/bjoc.15.217

• , we prepared a diarylethene incorporating the imidazo[1,2-a]pyridine moiety with ESIPT ability and reported the fluorescence switching of the system. Results and Discussion The diarylethene 1o having an ESIPT moiety was prepared by a coupling reaction of asymmetric diarylethene 3 [24] and 6-bromo-2-(2

Vicinal difunctionalization of alkenes by four-component radical cascade reaction of xanthogenates, alkenes, CO, and sulfonyl oxime ethers

• Shuhei Sumino,
• Takahide Fukuyama,
• Mika Sasano,
• Ilhyong Ryu,
• Antoine Jacquet,
• Frédéric Robert and
• Yannick Landais

Beilstein J. Org. Chem. 2019, 15, 1822–1828, doi:10.3762/bjoc.15.176

• competent substrates in the present four-component coupling reaction, affording 5f, albeit in modest yield. The reaction of 1a with 6-heptenenitrile (2e) and 5-hexen-2-one (2f) gave the corresponding four-component coupling products 5g and 5h, in 34 and 41% yield, respectively. The reaction with cyano

• -substituted sulfonyl oxime ester 3b also worked well to provide cyano-functionalized α-keto oximes. 5i, 5j, and 5k were thus accessible through the four-component coupling reaction between xanthogenates, alkenes, CO, and 3b in acceptable isolated yields (39–50%). Finally, the reaction between acetophenone

• mechanism. Concept: Alkene difuctionalization by four-component radical reaction using xanthates, alkenes, CO and sulfonyl oxime ethers. Four-component coupling reaction of ethyl 2-((ethoxycarbonothioyl)thio)acetate (1a), 1-octene (2a), CO, and sulfonyl oxime ether 3a under radical conditionsa. Supporting

Norbornadiene-functionalized triazatriangulenium and trioxatriangulenium platforms

• Roland Löw,
• Talina Rusch,
• Tobias Moje,
• Fynn Röhricht,
• Olaf M. Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1815–1821, doi:10.3762/bjoc.15.175

• decomposition, which is a necessary precondition for ultra-high vacuum STM investigations. The 3-bromo-2-cyano-substituted norbornadiene 4 was synthesized as described in the literature (Scheme 1) [10][11][12]. 4 was converted to 5 with trimethylsilylacetylene (72%) in a Sonogashira cross-coupling reaction. The

• obtained in a convergent synthesis (Scheme 2). Boronic ester 9 was synthesized as described in the literature [15]. In a Suzuki cross-coupling reaction norbornadiene 4 was coupled with 9 to the extended norbornadiene 10 (38%), which was attached to the TATA platform 6 to yield the extended norbornadiene

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• coupling reaction for the synthesis of 2-triazolylimidazo[1,2-a]pyridine 74 (Scheme 26) [31]. The reaction involved the use of copper oxide as a catalyst and sodium ascorbate as a reducing agent using triazolyl aldehyde 73, amidine 3 and terminal alkynes 2 as reaction substrates at 70 °C (Scheme 26). Here

• of the common reactants with 2-aminopyridines/2-aminoquinolines/1-aminoisoquinolines 3, 75, 76 to give the desired products, respectively (Scheme 27). Both EWGs and EDGs on the reactants resulted in good to excellent yields of the product. This process followed two types of coupling reaction

• protocol also provided a concise route for the synthesis of the antiulcer drug zolimidine in 95% yield. A three-component coupling reaction (3-CCR) for the synthesis of N-fused pyridines was reported by Balijapalli and Iyer [40]. The reaction was catalyzed by CuO/CuAl2O4 and ᴅ-glucose. The reaction had

Synthesis of 9-O-arylated berberines via copper-catalyzed C_Ar–O coupling reactions

• Qiaoqiao Teng,
• Xinhui Zhu,
• Qianqian Guo,
• Weihua Jiang,
• Jiang Liu and
• Qi Meng

Beilstein J. Org. Chem. 2019, 15, 1575–1580, doi:10.3762/bjoc.15.161

• leading to the failure of direct BBRB cross coupling. 9-O-Aryl berberine scope via cross-coupling reaction. 9-O-Ph-linked berberine dimer through double cross-coupling reaction. Optimization of the reaction conditions.a Supporting Information Supporting Information File 138: Experimental details and

Diazocine-functionalized TATA platforms

• Roland Löw,
• Talina Rusch,
• Fynn Röhricht,
• Olaf Magnussen and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 1485–1490, doi:10.3762/bjoc.15.150

• a function of electronic coupling (conjugation) of the azo unit to gold. The para-diazocine-TATA 1 was synthesized in a 5-step synthesis route (Scheme 1). Bromotoluene 3 was synthesized as described [26]. In a Sonogashira cross-coupling reaction acetylene-substituted toluene 5 was prepared from

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• starting material, but also ring fusion to selenophene was achieved by Cu-catalyzed C–Se cross-coupling reaction [28]. The detailed geometric structure and the packing behaviour in the solid state of triacenes 2–4 have been elucidated by single crystal X-ray structure analysis and X-ray diffraction on

• reinvestigated the synthesis of DTT 1 by using a Cu-catalyzed C–S cross-coupling reaction with potassium sulfide (K2S) as sulfur source [29]. The best results for this C–S ring-closure reaction were achieved by reacting 3,3’-diiodo-2,2’-bithiophene (5) [30] with the system K2S and copper iodide (CuI) as catalyst

• deprotection with TBAF in 66% yield, with selenourea and copper oxide nanoparticles surprisingly did not lead to any targeted DSS 4 in the attempted C–Se cross-coupling reaction. The structures of the prepared novel selenolotriacenes 2–4 and known DTT 1 were characterized by means of NMR spectroscopy

Selective detection of DABCO using a supramolecular interconversion as fluorescence reporter

• Indrajit Paul,
• Debabrata Samanta,
• Sudhakar Gaikwad and
• Michael Schmittel

Beilstein J. Org. Chem. 2019, 15, 1371–1378, doi:10.3762/bjoc.15.137

• in Scheme 1. Therefore, ligands 1 and 2 were synthesized by a palladium-catalyzed Sonogashira coupling reaction (Supporting Information File 1). All compounds were fully characterized by 1H NMR, 1H,1H-COSY, UV–vis, ESIMS and elemental analysis (Supporting Information File 1). Subsequently, we

N-doped carbon dots covalently functionalized with pillar[5]arenes for Fe³⁺ sensing

• Jia Gao,
• Ming-Xue Wu,
• Dihua Dai,
• Zhi Cai,
• Yue Wang,
• Wenhui Fang,
• Yan Wang and
• Ying-Wei Yang

Beilstein J. Org. Chem. 2019, 15, 1262–1267, doi:10.3762/bjoc.15.123

• ) through covalent bonds formed by EDC-NHS coupling reaction. The comparison of CCDs with single CN-dots without CP[5], revealed that the CCDs exhibit a higher selectivity for Fe3+ detection (Scheme 1). Fe3+ ions play an important role in the living organism and is related to many diseases, thus it is vital

• surface of CN-dots via EDC-NHS coupling reaction. Compared with unmodified CN-dots, CCDs demonstrated novel properties after the introduction of CP[5], and showed a higher selective sensing ability for Fe3+ ions. Hopefully, this strategy will inspire the design of new fluorescent chemical sensors toward

Insertion of [1.1.1]propellane into aromatic disulfides

• Robin M. Bär,
• Gregor Heinrich,
• Martin Nieger,
• Olaf Fuhr and
• Stefan Bräse

Beilstein J. Org. Chem. 2019, 15, 1172–1180, doi:10.3762/bjoc.15.114

• opening of 1 with Grignard reagents enables the synthesis of aryl and some alkyl-substituted BCPs and a subsequent cross-coupling reaction [5][18]. To provide bicyclo[1.1.1]pentylamine as a building block in large-scale syntheses, Bunker et al. developed a synthesis of hydrazine BCP via a manganese

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• palladium-catalysed reactions (Scheme 38). The first one is a Sonogashira coupling reaction between the terminal alkyne of propiolamide 128 and aryl iodide 129, which is preferred to the Suzuki–Miyaura reaction between aryl iodide 129 and boronic acid 130 present in the reaction mixture. Then, an internal

• series of 3-methyleneisoindolin-1-ones 13 were obtained (Scheme 2) [77]. Several aromatic and heteroaromatic substituents can be introduced in the exocyclic methylene position with high regioselectivity. It is noteworthy that arylalkynylcarboxilic acids 11 (R2 = Ar) can be obtained easily by the coupling

• reaction of propiolic acid and aryl halides [78]. Furthermore, the authors have been able to carry out the reaction in a sequential manner starting from propiolic acid and aryl iodides in the presence of caesium carbonate and a palladium catalyst. Next, addition of 2-iodobenzoic acid and ammonium acetate

Solid-phase synthesis of biaryl bicyclic peptides containing a 3-aryltyrosine or a 4-arylphenylalanine moiety

• Iteng Ng-Choi,
• Àngel Oliveras,
• Lidia Feliu and
• Marta Planas

Beilstein J. Org. Chem. 2019, 15, 761–768, doi:10.3762/bjoc.15.72

• cross-coupling reaction [15][16][17][18][19] or via a Pd-catalyzed C–H activation reaction [20][21]. We have used the former reaction for the solid-phase preparation of biaryl cyclic peptides bearing a Phe-Phe, a Phe-Tyr or a Tyr-Tyr linkage [22][23]. Our approach involved the synthesis of the linear

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• (NB4exp). The coupling reaction in aqueous buffer at pH 7.5 finally affords ArM 5, ArM 6 and ArM 7, respectively (Scheme 16). The obtained hybrid catalysts were tested for the RCM with substrates 21 and 64 (Table 9). Overall, ArM 6 and ArM 7 are comparable and perform best in both reactions with 35

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

Synthesis of C₃-symmetric star-shaped molecules containing α-amino acids and dipeptides via Negishi coupling as a key step

• Sambasivarao Kotha and
• Saidulu Todeti

Beilstein J. Org. Chem. 2019, 15, 371–377, doi:10.3762/bjoc.15.33

• containing unusual AAA units through cyclotrimerization and Negishi cross-coupling reaction as key steps under operationally simple reaction conditions. Here, we have used the readily available starting materials 4-iodoacetophenone (8) and L-serine (3). The C3-symmetric building blocks prepared were coupled

• , 2928, 1606, 1596, 1434, 783, 505 cm−1. Exemplar C3-symmetric peptide scaffolds reported in the literature. Preparation of compound 7 from L-serine (3). Preparation of the trimerized product 9. Synthesis of compound 11 via Negishi cross-coupling reaction. Synthesis of C3-symmetric trimers 12, 13 and 14

A novel and efficient synthesis of phenanthrene derivatives via palladium/norbornadiene-catalyzed domino one-pot reaction

• Yue Zhong,
• Wen-Yu Wu,
• Shao-Peng Yu,
• Tian-Yuan Fan,
• Hai-Tao Yu,
• Nian-Guang Li,
• Zhi-Hao Shi,
• Yu-Ping Tang and
• Jin-Ao Duan

Beilstein J. Org. Chem. 2019, 15, 291–298, doi:10.3762/bjoc.15.26

• and natural products. Results and Discussion We initiated our investigations by evaluating the three-component cross-coupling reaction of 2-iodotoluene (1a), ortho-bromobenzoyl chloride (2a) and norbornadiene, and we optimized the reaction conditions [21]. Firstly, the reaction took place under Pd

Molecular iodine-catalyzed one-pot multicomponent synthesis of 5-amino-4-(arylselanyl)-1H-pyrazoles

• Camila S. Pires,
• Daniela H. de Oliveira,
• Maria R. B. Pontel,
• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Diego Alves,
• Raquel G. Jacob and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2018, 14, 2789–2798, doi:10.3762/bjoc.14.256

• methodologies describing the transition metal-catalyzed cross-coupling reaction of diorganyl diselenides with (hetero)aryl, alkenyl, and alkynyl halides or pseudo-halides [3], an updated protocol that describe reduced waste generation and atom-economy is desired. In this context, the multicomponent cyclization

DABCO- and DBU-promoted one-pot reaction of N-sulfonyl ketimines with Morita–Baylis–Hillman carbonates: a sequential approach to (2-hydroxyaryl)nicotinate derivatives

• Soumitra Guin,
• Raman Gupta,
• Debashis Majee and
• Sampak Samanta

Beilstein J. Org. Chem. 2018, 14, 2771–2778, doi:10.3762/bjoc.14.254

• afforded 68% and 70% yields of 5ai and 5aj, respectively. Interestingly, the coupling reaction proceeded nicely not only with N-sulfonyl ketamine 1d bearing an electron poor Br atom but also substrates 1b and 1c having electron donating substituents (Me, MeO) on the aryl rings, although the latter produced

Synthesis and biological evaluation of 1,2-disubstituted 4-quinolone analogues of Pseudonocardia sp. natural products

• Stephen M. Geddis,
• Teodora Coroama,
• Suzanne Forrest,
• James T. Hodgkinson,
• Martin Welch and
• David R. Spring

Beilstein J. Org. Chem. 2018, 14, 2680–2688, doi:10.3762/bjoc.14.245

• first developed a strategy which constructed natural products 1–4 by uniting the quinolone cores with the side chain by means of an sp2–sp3 Suzuki–Miyaura coupling reaction [8]. Whilst these compounds unfortunately provided no modulation of PQS quorum screening (as determined using a heterologous

Novel solid-phase strategy for the synthesis of ligand-targeted fluorescent-labelled chelating peptide conjugates as a theranostic tool for cancer

• Sagnik Sengupta,
• Mena Asha Krishnan,
• Premansh Dudhe,
• Ramesh B. Reddy,
• Bishnubasu Giri,
• Sudeshna Chattopadhyay and
• Venkatesh Chelvam

Beilstein J. Org. Chem. 2018, 14, 2665–2679, doi:10.3762/bjoc.14.244

• diagnosis and deep tissue imaging of cancers and inflammatory diseases. Near infrared fluorophores containing a free or activated carboxylic group (e.g., IRDye 800CW NHS ester) can also be conjugated with the peptidic spacer using this methodology through amide coupling reaction. Moreover, the bioconjugates

• bed and washed with DCM (3 × 5 mL). The solvent was evaporated under reduced pressure and the crude product was purified through column chromatography (hexane/ethyl acetate = 50:50) to afford the tris(tert-butoxy)-protected DUPA precursor 4 which was further used for peptide coupling reaction in the

• added to the peptide vessel containing resin beads and the coupling reaction was continued for 6 h. The resin beads were washed with DMF (3 × 5 mL) followed by the washing with isopropanol (3 × 3 mL). Completion of the peptide coupling reaction was confirmed by performing the Kaiser test (KT). Then a

Transition metal-free oxidative and deoxygenative C–H/C–Li cross-couplings of 2H-imidazole 1-oxides with carboranyl lithium as an efficient synthetic approach to azaheterocyclic carboranes

• Lidia A. Smyshliaeva,
• Mikhail V. Varaksin,
• Pavel A. Slepukhin,
• Oleg N. Chupakhin and
• Valery N. Charushin

Beilstein J. Org. Chem. 2018, 14, 2618–2626, doi:10.3762/bjoc.14.240

• cross-coupling reaction of 2,2-dimethyl-4-phenyl-2H-imidazole 1-oxide (1a) with carboranyllithium 2 was chosen as a model reaction. It has finally been found that the best yield of 4a is achieved using AcCl as a deoxygenative agent at room temperature with stirring of the resulted reaction mixture for