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

• [68] applied to 3b provided 8b in only 25% 19F NMR yield. To extend the synthetic utility of the pyridine-mediated derivatization of aryldiazonium tetrafluoroborates we investigated the reaction with iodobenzene and iodine as efficient scavengers of aryl radicals [83][84]. A competitive experiment

Development of variously functionalized nitrile oxides

• Haruyasu Asahara,
• Keita Arikiyo and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2015, 11, 1241–1245, doi:10.3762/bjoc.11.138

• -methylcarbamoyl functional group. The synthetic utility of nitrile oxide 2 will be indeed improved by converting the N-methylcarbamoyl group into other functionalities, i.e., nitrile oxide 2 may serve as an equivalent of nitrile oxides 4 having versatile functional groups (Scheme 1). Weinreb amide (N-methoxy-N

• activation of the carbamoyl group and for preventing over-addition by organometallic reagents. Isoxazole-3-carboxamide 3 was successfully converted in a similar fashion. Thus, as shown in Figure 1, nitrile oxide 2 serves as an equivalent of functionalized nitrile oxides 4, thereby improving the synthetic

• utility of carbamoylnitrile oxide 2. Experimental Conversion of isoxazolecarboxamide 3 to 5c via tosyl derivative 12 To a solution of amide 3 (101 mg, 0.5 mmol) in THF (1 mL), a suspension of 60 wt % sodium hydride (100 mg, 2.5 mmol) in THF (3 mL) was added under argon. After the mixture was stirred

Multivalent polyglycerol supported imidazolidin-4-one organocatalysts for enantioselective Friedel–Crafts alkylations

• Tommaso Pecchioli,
• Manoj Kumar Muthyala,
• Rainer Haag and
• Mathias Christmann

Beilstein J. Org. Chem. 2015, 11, 730–738, doi:10.3762/bjoc.11.83

• immobilization of imidazolidin-4-one onto hyperbranched polyglycerol (hPG) and its application as multivalent organocatalyst. Results and Discussion To explore the synthetic utility of hPG in organocatalysis, we here report the synthesis and application of a series of three multivalent dendronized imidazolidin-4

2-(1-Hydroxypropyn-2-yl)-1-vinylpyrroles: the first successful Favorsky ethynylation of pyrrolecarbaldehydes

• A. V. Ivanov,
• V. S. Shcherbakova,
• I. A. Ushakov,
• L. N. Sobenina,
• O. V. Petrova,
• A. I. Mikhaleva and
• B. A. Trofimov

Beilstein J. Org. Chem. 2015, 11, 228–232, doi:10.3762/bjoc.11.25

• synthetic utility of the 2-(1-hydroxypropyn-2-yl)pyrroles formed. Results and Discussion After comparative analysis of the available literature data [21][22][23] and consequent optimization of the reaction conditions we have found that the superbasic catalytic composition NaOH/EtOH/DMSO (the molar ratio 1

Synthesis of dinucleoside acylphosphonites by phosphonodiamidite chemistry and investigation of phosphorus epimerization

• William H. Hersh

Beilstein J. Org. Chem. 2015, 11, 184–191, doi:10.3762/bjoc.11.19

• acylphosphonites are essentially unknown, acylphosphonates 3 (Figure 1) have been extensively studied over the past few decades [32], both for their synthetic utility [33][34][35][36][37] and as compounds of biological interest [38][39]. They have also been used for phosphorothioate synthesis, as will be described

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• /alkoxylation of amides pre-dates this work [12][13], Shono showed the synthetic utility of combining an electroorganic step with key carbon–carbon bond forming reactions required in synthetic organic chemistry. The key anodic methoxylation is operationally straightforward with a standard electrochemical set-up

Photorelease of phosphates: Mild methods for protecting phosphate derivatives

• Sanjeewa N. Senadheera,
• Abraham L. Yousef and
• Richard S. Givens

Beilstein J. Org. Chem. 2014, 10, 2038–2054, doi:10.3762/bjoc.10.212

• intact or rearrange to more strongly absorbing chromophores which compete for the effective radiation wavelengths, often resulting in incomplete conversions that compromise their synthetic utility. These chromophores and especially their photoproducts are also highly fluorescent, which frequently prove

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

• demonstrated the isolation and synthetic utility of a nucleoside phosphonium salt [28]. Thus, to us the reaction of oximes with BOP was an intriguing result, leading us to query whether a benzotriazolyl intermediate, rather than a phosphonium ion, was formed en route to the cyanide. This line of reasoning

The search for new amphiphiles: synthesis of a modular, high-throughput library

• George C. Feast,
• Thomas Lepitre,
• Xavier Mulet,
• Charlotte E. Conn,
• Oliver E. Hutt,
• G. Paul Savage and
• Calum J. Drummond

Beilstein J. Org. Chem. 2014, 10, 1578–1588, doi:10.3762/bjoc.10.163

• double-chain amphiphiles are presented in Table 2. Almost all compounds were synthesised in very good to excellent yields. The yields were consistent both in terms of the sugar head group and the length and nature of the tail, emphasising the synthetic utility of this route towards amphiphile synthesis

Design and synthesis of multivalent neoglycoconjugates by click conjugations

• Feiqing Ding,
• Li Ji,
• Ronny William,
• Hua Chai and
• Xue-Wei Liu

Beilstein J. Org. Chem. 2014, 10, 1325–1332, doi:10.3762/bjoc.10.134

• /glycosylation of the glycal shown in Figure 1 [49][50][51][52][53]. Extending the synthetic utility of this protocol, herein, we wish to report the synthetic modification of α-GalNAc-linked glycopeptides to 3-tosylamino-2,3-dideoxyneoglycoconjugates via click conjugations (Figure 2). Given the success in using

Visible-light photoredox catalyzed synthesis of pyrroloisoquinolines via organocatalytic oxidation/[3 + 2] cycloaddition/oxidative aromatization reaction cascade with Rose Bengal

• Carlos Vila,
• Jonathan Lau and
• Magnus Rueping

Beilstein J. Org. Chem. 2014, 10, 1233–1238, doi:10.3762/bjoc.10.122

• . Incorporation of methoxy groups at C-6 and C-7 in the dihydroisoquinoline core was well tolerated, affording the corresponding product 3fa in 68% yield. To demonstrate the synthetic utility of the oxidation/[3 + 2] cycloaddition/aromatization cascade we examined other dipolarophiles such as activated alkynes 5

Direct and indirect single electron transfer (SET)-photochemical approaches for the preparation of novel phthalimide and naphthalimide-based lariat-type crown ethers

• Dae Won Cho,
• Patrick S. Mariano and
• Ung Chan Yoon

Beilstein J. Org. Chem. 2014, 10, 514–527, doi:10.3762/bjoc.10.47

• ethers that possess different types of polyheteroatom containing side chains. Another observation that is related to the synthetic utility of SET-promoted photocyclization reactions driven by chemoselective desilylation of intermediate zwitterionic radicals comes from photochemical investigations of α

Efficient carbon-Ferrier rearrangement on glycals mediated by ceric ammonium nitrate: Application to the synthesis of 2-deoxy-2-amino-C-glycoside

• Alafia A. Ansari,
• Y. Suman Reddy and
• Yashwant D. Vankar

Beilstein J. Org. Chem. 2014, 10, 300–306, doi:10.3762/bjoc.10.27

• obtained the α-C-glycosides in an efficient manner, we explored their synthetic utility to synthesize a 2-deoxy-2-amino-α-C-glycoside. 2-Deoxy-2-amino-α-C-glycosides have received considerable attention in recent years due to their use in the synthesis of glycopeptides [50][51], glycolipids [51] and

Ambient gold-catalyzed O-vinylation of cyclic 1,3-diketone: A vinyl ether synthesis

• Yumeng Xi,
• Boliang Dong and
• Xiaodong Shi

Beilstein J. Org. Chem. 2013, 9, 2537–2543, doi:10.3762/bjoc.9.288

• the use of 1 mol % Echavarren catalyst t-BuXPhosAu(MeCN)SbF6 gave a slightly lower yield (71%), and the combination of 1 mol % t-BuXPhosAu(MeCN)SbF6 and 1 mol % Cu(OTf)2 gave 86% yield (under otherwise identical conditions). This result highlights the synthetic utility of TA-Au catalyst in the

The chemistry of amine radical cations produced by visible light photoredox catalysis

• Jie Hu,
• Jiang Wang,
• Theresa H. Nguyen and
• Nan Zheng

Beilstein J. Org. Chem. 2013, 9, 1977–2001, doi:10.3762/bjoc.9.234

• approach to exploit synthetic utility of photogenically produced amine radical cations. Reductive quenching of the photoexcited state of a photocatalyst (M) by amine 1 is governed by the reduction potentials of the photoexcited state and the amine (Scheme 1). The amine’s reduction potential, which can be

• cleavage reaction to 1,2-diamines, simultaneously generating two classes of synthetically useful intermediates, iminium ions (e.g., 133, Scheme 30) and α-amino radicals (e.g., 134, Scheme 30) [102]. The authors then exploited the synthetic utility of these two classes of intermediates. Irradiation of

Gold(I)-catalysed one-pot synthesis of chromans using allylic alcohols and phenols

• Eloi Coutant,
• Paul C. Young,
• Graeme Barker and
• Ai-Lan Lee

Beilstein J. Org. Chem. 2013, 9, 1797–1806, doi:10.3762/bjoc.9.209

• solvent to push the reaction to completion. Finally, to show the synthetic utility of this procedure, a hydroquinone (trimethylhydroquinone TMHQ (5l)) was also evaluated, as TMHQ is commonly used towards the synthesis of vitamin E and its analogues [17][21]. For solubility issues, dioxane is used as the

The application of a monolithic triphenylphosphine reagent for conducting Ramirez gem-dibromoolefination reactions in flow

• Kimberley A. Roper,
• Malcolm B. Berry and
• Steven V. Ley

Beilstein J. Org. Chem. 2013, 9, 1781–1790, doi:10.3762/bjoc.9.207

• performing this reaction in flow at 0 °C. Loading the monolith using the protocol described above was found to give an approximate active loading of 0.6 mmol for the Appel reaction. Utilising one monolith for both reactions potentially broadens the synthetic utility of the supported reagent and so performing

Gold-catalyzed intermolecular coupling of sulfonylacetylene with allyl ethers: [3,3]- and [1,3]-rearrangements

• Jungho Jun,
• Hyu-Suk Yeom,
• Jun-Hyun An and
• Seunghoon Shin

Beilstein J. Org. Chem. 2013, 9, 1724–1729, doi:10.3762/bjoc.9.198

• of an excess component. Expanding upon the intermolecular coupling reactions of readily available alkenes with alkynes would significantly enhance the synthetic utility of gold catalysis and therefore should find fruitful applications. While it has been known for a long time that allyl alcohols

α-Bromodiazoacetamides – a new class of diazo compounds for catalyst-free, ambient temperature intramolecular C–H insertion reactions

• Åsmund Kaupang and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2013, 9, 1407–1413, doi:10.3762/bjoc.9.157

• cyclic amide side chains. Keywords: α-halo-β-lactam; diazo; halocarbonylcarbene; halogenation; thermolysis; Introduction Diazocarbonyl compounds are popular precursors for carbonylcarbenes and -carbenoids, the synthetic utility of which is thoroughly established through their successful employment in

• temperature thermolysis of the resulting α-halodiazoacetamides. The synthetic utility of the α-bromodiazoacetamides has been demonstrated in the preparation of bicyclic α-bromo-β-lactams. In the cases where C–H insertion is conformationally favoured, the α-bromo-β-lactams were obtained in good to excellent

Tandem dinucleophilic cyclization of cyclohexane-1,3-diones with pyridinium salts

• Mostafa Kiamehr,
• Firouz Matloubi Moghaddam,
• Satenik Mkrtchyan,
• Volodymyr Semeniuchenko,
• Linda Supe,
• Alexander Villinger,
• Peter Langer and
• Viktor O. Iaroshenko

Beilstein J. Org. Chem. 2013, 9, 1119–1126, doi:10.3762/bjoc.9.124

• . Further studies to extend the scope of the synthetic utility of these cyclizations are in progress in both of our laboratories. Experimental General Information Solvents were purchased from ACROS and directly used without further purification. Analytical thin-layer chromatography was performed on 0.20 mm

Intramolecular carbonickelation of alkenes

• Rudy Lhermet,
• Muriel Durandetti and
• Jacques Maddaluno

Beilstein J. Org. Chem. 2013, 9, 710–716, doi:10.3762/bjoc.9.81

• -nickel 2-Ni seems to govern the formation of the cyclized product. Particularly, the dimerization of 2-Ni threatens the synthetic utility of this reaction, as observed in the case of 1a. In an effort to escape this pathway, we tried to stabilize 2-Ni by using allyl moieties that would provide secondary

Titanium-mediated reductive cross-coupling reactions of imines with terminal alkynes: An efficient route for the synthesis of stereodefined allylic amines

• Kebin Mao,
• Guoqin Fan,
• Yuanhong Liu,
• Shi Li,
• Xu You and
• Dan Liu

Beilstein J. Org. Chem. 2013, 9, 621–627, doi:10.3762/bjoc.9.69

• imines using Ti(OiPr)4/2 c-C5H9MgCl reagent. Various substituted allylic amine derivatives were obtained in good yields and with excellent regioselectivity after hydrolysis or iodonolysis of the resulting azatitanacyclopentenes. Further studies on the synthetic utility of the resulting titanacyclic

Synthesis of SF₅-containing benzisoxazoles, quinolines, and quinazolines by the Davis reaction of nitro-(pentafluorosulfanyl)benzenes

• Petr Beier and
• Tereza Pastýříková

Beilstein J. Org. Chem. 2013, 9, 411–416, doi:10.3762/bjoc.9.43

• yields. Their synthetic utility was demonstrated by condensation reactions with carbonyl compounds or amines to provide SF5-containing quinolines and quinazolines, respectively. Keywords: benzisoxazoles; pentafluorosulfanyl group; quinazolines; quinolines; sulfurpentafluorides; Introduction Reactions

Intramolecular carbolithiation of N-allyl-ynamides: an efficient entry to 1,4-dihydropyridines and pyridines – application to a formal synthesis of sarizotan

• Wafa Gati,
• Mohamed M. Rammah,
• Mohamed B. Rammah and
• Gwilherm Evano

Beilstein J. Org. Chem. 2012, 8, 2214–2222, doi:10.3762/bjoc.8.250

• , which does confirm that our deprotonation/carbometallation sequence is not suitable for the preparation of C-2-substituted (1,4-dihydro)pyridines. Application to a formal synthesis of sarizotan To further probe the synthetic utility of our pyridine synthesis, we next envisioned its use for the synthesis

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

• reactor in terms of space–time turnovers and photon efficiency; however, the required 400 min irradiation to achieve reasonable conversion on a 1 mmol scale would likely cause difficulty in finding synthetic utility for the reactor [33][34]. It is also interesting to compare the efficiency of the reactor

• been shown to be unsuccessful under batch conditions. Nevertheless, the low flow rates and low concentrations involved limited output to 2.4 µmol/h, leaving significant questions over its synthetic utility [48][49][50]. Other redox chemistry to be performed by using titanium dioxide photocatalysts