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

• enormous progress over the past decade, and continues to attract a great deal of attention due to the highly efficient routes now available for elaborating aromatic rings. While reactions of this type have been known for decades [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22

• groups, as well as sterically hindered aromatic rings, all taking place at room temperature. Suzuki–Miyaura-type C–H coupling reactions are typically more tolerant of electron-withdrawing groups (3d, 3f, 3k) and ortho-substitution (3g) on the aryl ring. On the other hand, the reaction with 4

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• -protected isatins using the Ir/L5 complex, giving the products in high yields (up to 98%) and with good to excellent enantioselectivities (up to 95% ee, Scheme 9) [25]. Only 1 mol % catalyst and 2.2 mol % ligand were used in the reactions. Substituents attached to the aromatic rings of isatins and

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

• efforts to better comprehend the scope of this catalytic system, especially on features concerning the BARF salt effect [43][44] and electronic effects on the aromatic rings of the chiral ligands [45]. In 2014, Maguire at al reported the syntheses of N-heterocycles by the enantioselective insertion of

From steroids to aqueous supramolecular chemistry: an autobiographical career review

• Bruce C. Gibb

Beilstein J. Org. Chem. 2016, 12, 684–701, doi:10.3762/bjoc.12.69

• shown in Scheme 5 was not a particularly good host; the free rotation of the aromatic rings ensures a poorly defined cavity. Moreover, although we could insert a range of functional groups into this second row of aromatic rims simply by using substituted benzal bromides [15][16], generally these

• . Thus, treatment of the shown octa-bromide (Scheme 6) with resorcinol led to the insertion of a third row of aromatic rings and the corresponding deep-cavity cavitand [17][18]. This “weaving process” can be carried out with many resorcinol derivatives, but the necessity of using variations on the

Biosynthesis of α-pyrones

• Till F. Schäberle

Beilstein J. Org. Chem. 2016, 12, 571–588, doi:10.3762/bjoc.12.56

• -pyrones Dibenzo-α-pyrones (16) harbor the α-pyrone moiety in the middle part and consist of three ring structures (Figure 2). Aromatic rings are fused to edge c and e of the central 2-pyrone, yielding the basic structure of 16. Many dibenzo-α-pyrone-producing fungi have been described. However, it seems

Copper-mediated arylation with arylboronic acids: Facile and modular synthesis of triarylmethanes

• H. Surya Prakash Rao and
• A. Veera Bhadra Rao

Beilstein J. Org. Chem. 2016, 12, 496–504, doi:10.3762/bjoc.12.49

• variety of triarylmethanes through substitution of C(sp3)–OH in diarylmethanols with arylboronic acids (Scheme 1B). We reasoned that since diarylmethanols with two different aromatic rings can be made by a wide variety of methods [53][54] (e.g., addition of an aryl carbanion to an aryl aldehyde and a

• of ferrocene-1-yl(phenyl)methanol (9d) with phenyboronic acid (10a) was facile and it provided diphenylmethylferrocene (11p) without any difficulty in 71% yield. Modular synthesis of triarylmethanes The synthetic method that we developed, through which three different aromatic rings on the central

• principle, we present the synthesis of three examples of triarylmethanes 11q–s that bear three different aromatic rings (Table 3). The copper-catalyzed coupling reaction of phenyl(pyren-1-yl)methanol (9b) with 4-methoxyphenylboronic acid (10f) and benzo[b]thiophen-2-ylboronic acid (10k) provided the

Cascade alkylarylation of substituted N-allylbenzamides for the construction of dihydroisoquinolin-1(2H)-ones and isoquinoline-1,3(2H,4H)-diones

• Ping Qian,
• Bingnan Du,
• Wei Jiao,
• Haibo Mei,
• Jianlin Han and
• Yi Pan

Beilstein J. Org. Chem. 2016, 12, 301–308, doi:10.3762/bjoc.12.32

• % yield. It should be noted that the reactions of substrates bearing disubstituted aromatic rings were possible but resulted in lower yield (5fa and 5ga). On the other hand, the variation of the substituent on the nitrogen atom has also been examined. In the cases of N-ethyl (4h), N-isopropyl (4i), and N

Regioselective palladium-catalyzed ring-opening reactions of C1-substituted oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylates

• Michael Edmunds,
• Mohammed Abdul Raheem,
• Rebecca Boutin,
• Katrina Tait and
• William Tam

Beilstein J. Org. Chem. 2016, 12, 239–244, doi:10.3762/bjoc.12.25

• variety of substituents were chosen, including electron-withdrawing and donating groups, bulky groups, and aromatic rings, in order to examine the impact of steric and electronic changes at the C1 position. The greatest yield for the ring-opened derivative was obtained with the methyl substituent (88

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

• -ribofuranosyl purine derivatives began with a palladium-catalyzed cross coupling [45][46] to install the aromatic moieties to the 6-position of the purine ring. In order to accomplish efficient cross-couplings of a wide range of aromatic rings, we utilized three different protocols that were employed for Stille

Investigation of the role of stereoelectronic effects in the conformation of piperidones by NMR spectroscopy and X-ray diffraction

• Cesar Garcias-Morales,
• David Ortegón-Reyna and
• Armando Ariza-Castolo

Beilstein J. Org. Chem. 2015, 11, 1973–1984, doi:10.3762/bjoc.11.213

• rings on the six-membered ring with the boat conformation are antiperiplanar to the aromatic ring on the six-membered ring with the chair conformation (Figure 7a). This geometry allowed a C–H∙∙∙π intramolecular interaction between the aromatic rings. There are also C–H∙∙∙π intermolecular interactions

• 7 are reported for the first time. Crystals of 1 were obtained by slow evaporation of a saturated toluene solution, and 1 crystallized in the P21/n space group. The six-membered ring in the crystal structure exhibits a chair–boat conformation. For 1, the crystal structure shows that the aromatic

[2.2]Paracyclophane derivatives containing tetrathiafulvalene moieties

• Laura G. Sarbu,
• Lucian G. Bahrin,
• Peter G. Jones,
• Lucian M. Birsa and
• Henning Hopf

Beilstein J. Org. Chem. 2015, 11, 1917–1921, doi:10.3762/bjoc.11.207

• the rigid framework and the short distance between the two aromatic rings within the [2.2]paracyclophane unit. Besides investigations of the geometry and of transannular interactions, special attention has been paid to the ability of these compounds to form charge-transfer complexes [6][7][8][9]. A

The simple production of nonsymmetric quaterpyridines through Kröhnke pyridine synthesis

• Isabelle Sasaki,
• Jean-Claude Daran and
• Gérard Commenges

Beilstein J. Org. Chem. 2015, 11, 1781–1785, doi:10.3762/bjoc.11.193

• on C5 and C4, belonging to the aromatic ring substituted by the pinene moieties. These may impose some strain in the Pt complex, resulting in a slightly different electronic environment as compared to the other nonsubstituted aromatic rings. Crystals of compounds 5, 8 and 9 were obtained and their X

Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

• Louis P. Sandjo,
• Victor Kuete and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183

• in the fusion of aromatic rings, which makes this assignment a difficult task. An initial solution for structure determination might be to associate a single crystal X-ray structure to the NMR data. Unfortunately, the development of a suitable crystal for the crystallographic analysis is not an easy

Robust bifunctional aluminium–salen catalysts for the preparation of cyclic carbonates from carbon dioxide and epoxides

• Yuri A. Rulev,
• Zalina Gugkaeva,
• Victor I. Maleev,
• Michael North and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2015, 11, 1614–1623, doi:10.3762/bjoc.11.176

• one-component aluminium-based catalysts for the reaction between epoxides and carbon dioxide have been prepared. The catalysts are composed of aluminium–salen chloride complexes with trialkylammonium groups directly attached to the aromatic rings of the salen ligand. With terminal epoxides, the

• efficient for polycarbonate production [12]. Further modification of the salen moiety by the introduction of basic or ammonium salts through alkyl spacers attached to the salen aromatic rings led to the formation of a family of bifunctional catalysts possessing both Lewis acid and nucleophilic catalysis

• reactions [20][21][22][23]. We reasoned that the direct introduction of ammonium moieties onto the aromatic rings of the salen ligands (as in structures 1 and 2) would greatly stabilize the whole structure by reducing the number of sp3-hybridized carbon atoms attached to the nitrogen atoms of the ammonium

Design and synthesis of hybrid cyclophanes containing thiophene and indole units via Grignard reaction, Fischer indolization and ring-closing metathesis as key steps

• Sambasivarao Kotha,
• Ajay Kumar Chinnam and
• Mukesh E. Shirbhate

Beilstein J. Org. Chem. 2015, 11, 1514–1519, doi:10.3762/bjoc.11.165

• of 3 followed by an RCM of diindole 5 can deliver target molecule 1 (Route B). The advantages of these approaches are: one can vary the length of the alkene chain during the Grignard addition, and generate diverse cyclophanes of different ring size. Diverse aromatic rings can be incorporated by

Antioxidant potential of curcumin-related compounds studied by chemiluminescence kinetics, chain-breaking efficiencies, scavenging activity (ORAC) and DFT calculations

• Adriana K. Slavova-Kazakova,
• Silvia E. Angelova,
• Timur L. Veprintsev,
• Petko Denev,
• Davide Fabbri,
• Maria Antonietta Dettori,
• Maria Kratchanova,
• Vladimir V. Naumov,
• Aleksei V. Trofimov,
• Rostislav F. Vasil’ev,
• Giovanna Delogu and
• Vessela D. Kancheva

Beilstein J. Org. Chem. 2015, 11, 1398–1411, doi:10.3762/bjoc.11.151

• biphenylic structure provides lipophilicity to dimer 9 allowing for a strong effect against pests and plant diseases [15]. The different conformations of the biphenyl structure generated by selective functionalization of the aromatic rings led us to consider this moiety as a basic and valued framework for

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

• ][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] are strained organic molecules which contain aromatic ring(s) as well as aliphatic unit(s). The aromatic rings provide rigidity to their structure, whereas the aliphatic unit(s) form bridge

• (s) between the aromatic rings and also provide flexibility to the overall structure. Cyclophanes play an important role in “host–guest” chemistry [39][40][41][42][43] and supramolecular assembly [44][45][46][47]. “Phane”-containing molecules show interactions with π-systems, and they can also bind

New depsidones and isoindolinones from the mangrove endophytic fungus Meyerozyma guilliermondii (HZ-Y₂) isolated from the South China Sea

• Senhua Chen,
• Zhaoming Liu,
• Yayue Liu,
• Yongjun Lu,
• Lei He and
• Zhigang She

Beilstein J. Org. Chem. 2015, 11, 1187–1193, doi:10.3762/bjoc.11.133

• ; Meyerozyma guilliermondii; Introduction Depsidones are characterized by the presence of cyclic diaryl ethers with an ester link joining the two aromatic rings [1][2]. They have been isolated mainly from various lichens [3][4][5] and other fungi [6][7][8][9][10][11]. These metabolites displayed a wide range

• aromatic rings (I) and (III) should be linked by ether and an ester bridge, revealing a depsidone skeleton with a seven-membered ring (II). Thus, the structure of 1 was revealed as a new depsidone belonging to the same family compound of the botryorhodines A–D [6], named botryorhodine E. Botryorhodine F (2

Synthesis and surface grafting of a β-cyclodextrin dimer facilitating cooperative inclusion of 2,6-ANS

• Lars W. Städe,
• Thorbjørn T. Nielsen,
• Laurent Duroux,
• Reinhard Wimmer,
• Kyoko Shimizu and
• Kim L. Larsen

Beilstein J. Org. Chem. 2015, 11, 514–523, doi:10.3762/bjoc.11.58

• coplanar arrangement of the aromatic rings makes 2,6-ANS an excellent guest molecule, the dimensions of 2,6-ANS exceed the dimensions of the β-CD cavity and, therefore, potentially allow for formation of a 2:1 complex. This behavior has previously been reported for parent β-CD with the naphthalene

• complex with parent β-CD was observed. We speculated that a β-CD dimer prepared with a short spacer would allow for the formation of 1:1 complex (1:2 in terms of β-CD moieties) with molecules bearing extended aromatic rings (such as the 2,6-ANS used here as a model), thereby resulting in higher complex

3-Glucosylated 5-amino-1,2,4-oxadiazoles: synthesis and evaluation as glycogen phosphorylase inhibitors

• Marion Donnier-Maréchal,
• David Goyard,
• Vincent Folliard,
• Tibor Docsa,
• Pal Gergely,
• Jean-Pierre Praly and
• Sébastien Vidal

Beilstein J. Org. Chem. 2015, 11, 499–503, doi:10.3762/bjoc.11.56

• morpholinyl (Scheme 1, d) and piperidinyl (Scheme 1, e) residues were also selected as candidates for their hydrophobic properties, although they are bulkier than aromatic rings. The synthesis started with commercially available ureas (2a and 2e) or through the synthesis of such ureas. While the synthesis

Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo

• Alireza Shakoori,
• John B. Bremner,
• Mohammed K. Abdel-Hamid,
• Anthony C. Willis,
• Rachada Haritakun and
• Paul A. Keller

Beilstein J. Org. Chem. 2015, 11, 481–492, doi:10.3762/bjoc.11.54

• (IC50 3.06 µg/mL, 9.44 µM). While the introduction of a methyl substituent in the allylic moiety (spiro heterocycle 14) was detrimental to this activity, other possibilities exist for substituent variation at other sites, e.g., in the aromatic rings (starting with substituted indigo derivatives) and at

Bis(vinylenedithio)tetrathiafulvalene analogues of BEDT-TTF

• Erdal Ertas,
• İlknur Demirtas and
• Turan Ozturk

Beilstein J. Org. Chem. 2015, 11, 403–415, doi:10.3762/bjoc.11.46

• ][28][29][30] and fused aromatic rings [31][32][33][34] and the construction of molecules having acceptor substituents [35][36][37]. Generally, all these modifications served to produce molecules with better conjugation and improved S···S intermolecular and C–H···anion interactions in determining the

Attempts to prepare an all-carbon indigoid system

• Şeref Yildizhan,
• Henning Hopf and
• Peter G. Jones

Beilstein J. Org. Chem. 2015, 11, 363–372, doi:10.3762/bjoc.11.42

• structure 16 to the isolated dimer 17. Clearly, among these alternatives, the last route is preferred. In 17 the two benzene rings are anellated in anti-orientation, i.e., as far apart as possible. There exists an alternative structure, however, in which the two aromatic rings point in the same direction

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

• the two aromatic rings was shortened, and a series of compounds (Scheme 2) with different substitutions on the aromatic rings was synthesized to explore the role of stereoelectronic effects. It was demonstrated that these analogs of curcumin showed excellent anti-angiogenic activity with equivalent or

A facile synthesis of functionalized 7,8-diaza[5]helicenes through an oxidative ring-closure of 1,1’-binaphthalene-2,2’-diamines (BINAMs)

• Youhei Takeda,
• Masato Okazaki,
• Yoshiaki Maruoka and
• Satoshi Minakata

Beilstein J. Org. Chem. 2015, 11, 9–15, doi:10.3762/bjoc.11.2

• due to background side-reactions such as chlorination on the aromatic rings and oxidative oligomerization of BINAMs. Furthermore, this new oxidative method was found to be applicable in the ring-closing reaction of 1,1’-biphenyl-2,2’-diamine (3) leading to benzo[c]cinnoline (4) in a good yield