Synthesis and NMR studies of malonyl-linked glycoconjugates of N-(2-aminoethyl)glycine. Building blocks for the construction of combinatorial glycopeptide libraries

• Markus Nörrlinger,
• Sven Hafner and
• Thomas Ziegler

Beilstein J. Org. Chem. 2016, 12, 1939–1948, doi:10.3762/bjoc.12.183

• 2:1 which was in accordance with similar rotamers described in literature [22]. Hereupon, we report on our investigations concerning the structures of the fully protected conjugates 1 and 4 for the rotamers of which around the C–N bond we calculated the respective ΔG‡r-values. Results and Discussion

• bond (C–N bond) we calculated the corresponding ΔG‡r values for building blocks 1a,b from the measured coalescence temperatures (Tc) by using the Eyring model [26]. The ΔG‡c values of the dimeric glycoconjugate 4 could not be determined though because no unambiguous assignment of the rotameric

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

Catalytic Chan–Lam coupling using a ‘tube-in-tube’ reactor to deliver molecular oxygen as an oxidant

• Carl J. Mallia,
• Paul M. Burton,
• Alexander M. R. Smith,
• Gary C. Walter and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2016, 12, 1598–1607, doi:10.3762/bjoc.12.156

• ; oxygen; “tube-in-tube”; Introduction The functionalisation of aromatic and aliphatic amines has received considerable attention due to the number of biologically active compounds represented by these classes. For this reason different synthetic methods for C–N bond formation have been developed (Scheme

Microwave-assisted synthesis of (aminomethylene)bisphosphine oxides and (aminomethylene)bisphosphonates by a three-component condensation

• Erika Bálint,
• Ádám Tajti,
• Anna Dzielak,
• Gerhard Hägele and
• György Keglevich

Beilstein J. Org. Chem. 2016, 12, 1493–1502, doi:10.3762/bjoc.12.146

• step is the nucleophilic addition of diethyl phosphite to the C=N bond of the imines resulting in phosphonates III or IV, respectively. Then, the elimination of an amine or ethanol and the addition of another unit of diethyl phosphite may lead to (aminomethylene)bisphosphonates (VI). If the amine is in

The synthesis of functionalized bridged polycycles via C–H bond insertion

• Jiun-Le Shih,
• Po-An Chen and
• Jeremy A. May

Beilstein J. Org. Chem. 2016, 12, 985–999, doi:10.3762/bjoc.12.97

• access to multiple targets from a single intermediate produced on large scale that may be stored until needed [17]. The C–H bond insertion has great potential as a method to access different polycyclic isomers (e.g., 1 or 3) through C–C or C–N bond formation from a carbene or nitrene, respectively

Direct estimate of the internal π-donation to the carbene centre within N-heterocyclic carbenes and related molecules

• Diego M. Andrada,
• Nicole Holzmann,
• Thomas Hamadi and
• Gernot Frenking

Beilstein J. Org. Chem. 2015, 11, 2727–2736, doi:10.3762/bjoc.11.294

• carbene 8, which approaches a standard C–N single bond (1.46 Å) [104]. The Ccarb–N bond lengths exhibit otherwise a remarkable small range between 1.35–1.38 Å. The C–N bond is slightly longer in the conjugated 6π-electron carbenes which possess some aromatic character than in the non-aromatic analogues

• which previously ascribed to stronger π-conjugation [105][106][107]. The introduction of the heteroatoms O and S in compounds 11 and 12 changes the C–N bond only slightly. The Ccarb–C bond lengths in the conjugated carbenes are between 1.404 Å (9)–1.433 Å (14) while the cAAC system 6 has a much longer

Copper-catalyzed aminooxygenation of styrenes with N-fluorobenzenesulfonimide and N-hydroxyphthalimide derivatives

• Yan Li,
• Xue Zhou,
• Guangfan Zheng and
• Qian Zhang

Beilstein J. Org. Chem. 2015, 11, 2721–2726, doi:10.3762/bjoc.11.293

• . The aminooxygenation product could be converted into the corresponding alcohol or free amine through the cleavage of the N–O or C–N bond of the N-hydroxyphthalimide moiety. Keywords: aminooxygenation of styrenes; copper catalysts; N-fluorobenzenesulfonimide; N-hydroxyphthalimide derivatives

• the cleavage of the N–O or C–N bond of the NHPI moiety. Further studies are underway in our lab. Bioactive compounds containing 1,2-aminoalcohol motif. The copper-catalyzed three-component aminooxygenation of styrenes with NFSI and NHPI derivatives. Reaction conditions: 1 (0.9 mmol, 3.0 equiv), NFSI

Bifunctional phase-transfer catalysis in the asymmetric synthesis of biologically active isoindolinones

• Antonia Di Mola,
• Maximilian Tiffner,
• Francesco Scorzelli,
• Laura Palombi,
• Rosanna Filosa,
• Paolo De Caprariis,
• Mario Waser and
• Antonio Massa

Beilstein J. Org. Chem. 2015, 11, 2591–2599, doi:10.3762/bjoc.11.279

• ]. The racemization probably occurs on the product 9, via the mechanism reported in Scheme 3, as a slower process than the decarboxylation itself. The cleavage of the C–N bond and the formation of the acyclic intermediates 11 with the consequent loss of chirality is probably favored by the protonation of

Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

• David Porter,
• Belinda M.-L. Poon and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 2549–2556, doi:10.3762/bjoc.11.275

• ) are established catalysts of C–O bond formation, oxidising hydrocarbon substrates via hydroxylation, epoxidation and dihydroxylation pathways. Herein we report the capacity of these catalysts to promote C–N bond formation, via allylic amination of alkenes. The combination of N-Boc-hydroxylamine with

• cyclohexene (7) [45][46][47], we wished to explore potential C–N bond formation at this position using iron catalysis. Combining cyclohexene (7, in excess) with N-Boc-hydroxylamine (8) as the nitrogen source and the iron complex FeTPA (4) or FeBPMEN (5) afforded a mixture of products: the allylic

Recent advances in copper-catalyzed C–H bond amidation

• Jie-Ping Wan and
• Yanfeng Jing

Beilstein J. Org. Chem. 2015, 11, 2209–2222, doi:10.3762/bjoc.11.240

• copper catalysis is in the C–N bond formation by using carbon sources and nitrogen functional groups such as amides. In this review, the recent progress in the amidation reactions employing copper-catalyzed C–H amidation is summarized. Keywords: amidation; C–H bond; cascade reactions; Copper catalysis

• realized via a tandem Ullmann-type C–N coupling of the Ar–X bond and the amino group in 83 as well as the intramolecular amidation which was believed to assist the oxidative formation of the imine C=N bond (Scheme 22). By making use of this cascade synthetic method, Nagarajan et al. [78] finished the

• synthesis of various polycyclic structured quinazolinones 86 via corresponding starting materials 85 which were synthesized before by stepwise preparation (Scheme 22). Based on a similar strategy of combining an Ullmann C–N bond formation and C–H amidation, Fu and Xu [79] also achieved the cascade reactions

Copper-mediated synthesis of N-alkenyl-α,β-unsaturated nitrones and their conversion to tri- and tetrasubstituted pyridines

• Dimitra Kontokosta,
• Daniel S. Mueller,
• Dong-Liang Mo,
• Wiktoria H. Pace,
• Rachel A. Simpson and
• Laura L. Anderson

Beilstein J. Org. Chem. 2015, 11, 2097–2104, doi:10.3762/bjoc.11.226

• modularity of the Chan–Lam coupling process, and proceeds through a pathway that is distinct from the Liebeskind copper-catalyzed C–N bond coupling and electrocyclization (Scheme 2). Results and Discussion A Chan–Lam coupling between chalcone oxime 6a and cyclohexenylboronic acid (7a) was initially tested

Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides

• Hanmo Zhang,
• E. Ben Hay,
• Stephen J. Geib and
• Dennis P. Curran

Beilstein J. Org. Chem. 2015, 11, 1649–1655, doi:10.3762/bjoc.11.181

• hemiaminal 29 opens in the other direction (with C–N bond cleavage) to give an α-formyl-γ-amino lactam, which then undergoes C-to-N transformylation. The analysis of the crude reaction mixtures by TLC showed that the spots of formamides 25–27 were present early and grew in intensity with time as the

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• exo regioisomers. Results obtained in the present study show that naphthyl-oxazoline has a tendency to form exclusively endo-cyclic complexes with the C=N bond within a palladacycle. Furthermore, NMR data analyses demonstrate that the five-membered palladacycle 5a was preferentially formed upon the

Advances in the synthesis of functionalised pyrrolotetrathiafulvalenes

• Luke J. O’Driscoll,
• Sissel S. Andersen,
• Marta V. Solano,
• Dan Bendixen,
• Morten Jensen,
• Troels Duedal,
• Jess Lycoops,
• Cornelia van der Pol,
• Rebecca E. Sørensen,
• Karina R. Larsen,
• Kenneth Myntman,
• Christian Henriksen,
• Stinne W. Hansen and
• Jan O. Jeppesen

Beilstein J. Org. Chem. 2015, 11, 1112–1122, doi:10.3762/bjoc.11.125

• discussions here will be limited to copper-mediated C–N-bond formation, as we find this to be a flexible and convenient method. Recent work in our laboratory has involved the N-arylation of MPTTFs, including both unsubstituted and thioether-substituted examples (Scheme 6 and Table 3). These materials have

An intramolecular C–N cross-coupling of β-enaminones: a simple and efficient way to precursors of some alkaloids of Galipea officinalis

• Hana Doušová,
• Radim Horák,
• Zdeňka Růžičková and
• Petr Šimůnek

Beilstein J. Org. Chem. 2015, 11, 884–892, doi:10.3762/bjoc.11.99

• widely applied metal for C–N bond formation [50][51][52]. We then applied the CuI/[L] catalytic system to 3a (see method C in Supporting Information File 1, pages S25 and S26). The choice of the ligand is crucial here, as L7 (Figure 2) had no effect (Table 1, entry 6) whereas using another common ligand

Fluoride-driven ‘turn on’ ESPT in the binding with a novel benzimidazole-based sensor

• Kai Liu,
• Xiaojun Zhao,
• Qingxiang Liu,
• Jianzhong Huo,
• Bolin Zhu and
• Shihua Diao

Beilstein J. Org. Chem. 2015, 11, 563–567, doi:10.3762/bjoc.11.61

• characteristic bands centered at 410, 276 and 228 nm in CH3CN. Among these, the band in the region around 276 and 228 nm is attributed to the excitation of π electrons localized at the C=N bond and at the aromatic system [30], and the peak at 410 nm was ascribed to the intramolecular charge transition between

Azirinium ylides from α-diazoketones and 2H-azirines on the route to 2H-1,4-oxazines: three-membered ring opening vs 1,5-cyclization

• Nikolai V. Rostovskii,
• Mikhail S. Novikov,
• Alexander F. Khlebnikov,
• Galina L. Starova and
• Margarita S. Avdontseva

Beilstein J. Org. Chem. 2015, 11, 302–312, doi:10.3762/bjoc.11.35

• in energy, the reaction sequence 10j→13j→14j leading to [3.2.1] adduct 6j seems to be more reasonable than 10j→15j→14j due to the much higher concentrations of the reacting species. Actually, the activation barrier to the bicyclic C–N bond cleavage in 10j is very low, but the equilibrium between 10j

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• compounds [15], the Pd(II)-catalyzed oxidative C–C, C–O, and C–N bond formation [3], the transition metal-catalyzed etherification of unactivated C–H bonds [19], the Pd(II)-catalyzed oxidative functionalization at the allylic position of alkenes [20][21], the oxidative functionalization catalyzed by copper

Formal total syntheses of classic natural product target molecules via palladium-catalyzed enantioselective alkylation

• Yiyang Liu,
• Marc Liniger,
• Ryan M. McFadden,
• Jenny L. Roizen,
• Jacquie Malette,
• Corey M. Reeves,
• Douglas C. Behenna,
• Masaki Seto,
• Jimin Kim,
• Justin T. Mohr,
• Scott C. Virgil and
• Brian M. Stoltz

Beilstein J. Org. Chem. 2014, 10, 2501–2512, doi:10.3762/bjoc.10.261

• groups have pursued its total synthesis [74][75][76][77], including a number of enantioselective syntheses [78][79][80][81][82]. In 2001, Magnus reported a total synthesis of rhazinilam in racemic form (Scheme 10) [83]. In their approach, the first retrosynthetic disconnection of the amide C–N bond in

Derivatives of the triaminoguanidinium ion, 3. Multiple N-functionalization of the triaminoguanidinium ion with isocyanates and isothiocyanates

• Jan Szabo,
• Kerstin Karger,
• Nicolas Bucher and
• Gerhard Maas

Beilstein J. Org. Chem. 2014, 10, 2255–2262, doi:10.3762/bjoc.10.234

• Information File 1) reveals significant differences between the two structures. The C–N bond lengths of the guanidinium unit in 7a are equal (1.330(3)–1.333(3) Å) and indicate the full charge delocalization and partial double bond character of these bonds. In the neutral guanidine 8 this symmetry is lost; one

Exploration of C–H and N–H-bond functionalization towards 1-(1,2-diarylindol-3-yl)tetrahydroisoquinolines

• Michael Ghobrial,
• Marko D. Mihovilovic and
• Michael Schnürch

Beilstein J. Org. Chem. 2014, 10, 2186–2199, doi:10.3762/bjoc.10.226

• wanted to use direct functionalization either via C–H activation or cross dehydrogenative coupling for C–C-bond-forming reactions avoiding the use of two prefunctionalized building blocks. Naturally, C–N-bond formation should proceed via Buchwald–Hartwig coupling. The target molecules can be considered

Chemistry of polyhalogenated nitrobutadienes, 14: Efficient synthesis of functionalized (Z)-2-allylidenethiazolidin-4-ones

• Viktor A. Zapol’skii,
• Jan C. Namyslo,
• Mimoza Gjikaj and
• Dieter E. Kaufmann

Beilstein J. Org. Chem. 2014, 10, 1638–1644, doi:10.3762/bjoc.10.170

• -substituted anilines 16–18 two atropisomers were generated. This phenomenon is due to a less hindered rotation of the C–N bond of the former anilines (Figure 1). The steric hindrance is additionally forcing by the s-cis conformation of the nitrobutadiene moiety (cf. Figure 2). A DFT calculation of the energy

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

• phenanthrene synthesis [19]. A solution of o-biphenyldiazonium tetrafluoroborate in acetonitrile showed strong absorption between 400–500 nm with all light at the UV–vis edge at 400 nm being completely absorbed. This again indicates that direct photocleavage of the C–N bond might be operating. The cyclization

• Deronzier from 1984 [32]. The significant overlap of the absorption spectra of the arenediazonium salt recorded before and after the addition of eosin Y (Figure 4) suggests that direct photolysis of the C–N bond could account for the erosion of product yield in the catalytic process due to competitive

• heterolytic C–N bond cleavage toward highly reactive aryl cation species. The standard reaction conditions of many literature reports involve concentrations which are orders of magnitude higher than those suitable for absorption spectroscopy studies. This means that even very inefficient transitions (at

Addition of H-phosphonates to quinine-derived carbonyl compounds. An unexpected C9 phosphonate–phosphate rearrangement and tandem intramolecular piperidine elimination

• Łukasz Górecki,
• Artur Mucha and
• Paweł Kafarski

Beilstein J. Org. Chem. 2014, 10, 883–889, doi:10.3762/bjoc.10.85

• C8 resonance signal was consequently shifted from 60 ppm to approximately 120 ppm. The aromatic system remained intact. These data suggest formation of the C8=C9 double bond in a cascade process with concomitant cleavage of the C–N bond that follows the phosphonate–phosphate rearrangement (Scheme 6

Domino reactions of 2H-azirines with acylketenes from furan-2,3-diones: Competition between the formation of ortho-fused and bridged heterocyclic systems

• Alexander F. Khlebnikov,
• Mikhail S. Novikov,
• Viktoriia V. Pakalnis,
• Roman O. Iakovenko and
• Dmitry S. Yufit

Beilstein J. Org. Chem. 2014, 10, 784–793, doi:10.3762/bjoc.10.74

• the formation of dihydropyrazines 11 via azirine–nitrile ylide isomerization cannot compete with reaction of azirines with acylketenes (Figure 2). Dimerization of azirine 2a via nucleophilic attack of the nitrogen lone pair of one azirine molecule on the C=N bond of another is also energetically

• unfavourable (ΔG# = 53.6 kcal·mol−1, 353 K, benzene (PCM)). In contrast to this, the nucleophilic attack of the nitrogen lone pair of azirine 2 on the C=N bond of protonated azirine 14 and consequent cyclization to dihydropyrazine 15 proceeds via quite low barriers (Figure 4). By comparison of the data