Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• oxidation as well as the oxidation and deprotonation of the radical benzothiophene precursors are accomplished by a [CoIII] catalyst in a second catalytic cycle. [CoIII] is stepwise reduced to [CoI]. Protonation leads to a [CoIII] hydride complex generating dihydrogen by protonation. Quantitative H2

Aminosugar-based immunomodulator lipid A: synthetic approaches

• Alla Zamyatina

Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3

• diglucosamine backbone of lipid A which allows for a stepwise introduction of multiple functional groups into the molecule are discussed. Thorough consideration is also given to the synthesis of 1,1′-glycosyl phosphodiesters comprising partial structures of 4-amino-4-deoxy-β-L-arabinose modified Burkholderia

• substructures substituted by one Kdo residue at position 6’ and/or modified with ethanolamine at the glycosidic phosphate were accomplished just recently [21][87][88]. The synthetic strategy relied on the initial preparation of fully orthogonally protected βGlcN(1→6)GlcN disaccharide which was then stepwise

• permanent benzyl/benzylidene acetal protections for hydroxyl groups and application of 9-fluorenylmethoxycarbamate (Fmoc) and azido protecting groups for masking the NH2 functionalities allowed for the stepwise instalment of functional groups (phosphates and fatty acids) into the diglucosamine 44. For the

Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles

• Vivek Poonthiyil,
• Thisbe K. Lindhorst,
• Vladimir B. Golovko and
• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 11–24, doi:10.3762/bjoc.14.2

• SPAAC in their one-pot stepwise preparation of GAuNPs, and then used those particles as supramolecular glycoprobes for the rapid serological recognition of a cancer biomarker. Firstly, ligand exchange was performed on Cit-AuNPs by reaction with a THF solution of a cyclooctyne disulfide and an aqueous

What contributes to an effective mannose recognition domain?

• Christoph P. Sager,
• Deniz Eriş,
• Martin Smieško,
• Rachel Hevey and
• Beat Ernst

Beilstein J. Org. Chem. 2017, 13, 2584–2595, doi:10.3762/bjoc.13.255

• -energy transition state. This can be explained by the stepwise dissociation and subsequent rehydration that are required for ligand displacement (inset, Figure 2B), due to the inherently shielded nature of the buried binding site. In contrast, solvent exposed H-bonds can be more easily substituted by

A concise flow synthesis of indole-3-carboxylic ester and its derivatisation to an auxin mimic

• Marcus Baumann,
• Ian R. Baxendale and
• Fabien Deplante

Beilstein J. Org. Chem. 2017, 13, 2549–2560, doi:10.3762/bjoc.13.251

• ) mediated reduction and is consistent with a stepwise reduction mechanism (Scheme 5) [27][28][29]. It is evident from the sequence that several equivalents of hydrogen are necessary for full reduction and as a result a higher concentration (pressure) of hydrogen would be beneficial (Table 2, entries 4–10

• for the synthesis intermediate 11. Stepwise reduction of intermediate 11 under hydrogenation conditions. * Indicates potential tautomeric structure. Species in parentheses are proposed transient intermediates. Flow sequence for the construction of product 8. Assembled process for flow synthesis of

Exploring mechanochemistry to turn organic bio-relevant molecules into metal-organic frameworks: a short review

• Vânia André,
• Sílvia Quaresma,
• João Luís Ferreira da Silva and
• M. Teresa Duarte

Beilstein J. Org. Chem. 2017, 13, 2416–2427, doi:10.3762/bjoc.13.239

• carried out with success. These studies show the propensity for stepwise mechanisms, especially in case of ZIFs, with a low density or a highly solvated product often formed first which is then transformed into increasingly dense, less solvated materials, resembling Ostwald’s rule of stages [8][102][103

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• ), an electron-rich (1b) and electron-poor (1c) propiolic acid substrate (Scheme 4, Table 4). Although the electroneutral and electron-rich substrates give good to excellent yields in the sequence (Table 4, entries 1–3), even higher (Table 4, entry 1) than for a stepwise synthesis furnishing an overall

Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines

• Satoru Mori and
• Norio Shibata

Beilstein J. Org. Chem. 2017, 13, 2273–2296, doi:10.3762/bjoc.13.224

• compared with homodimers [141]. This heterodimer was synthesized by a stepwise synthesis method in which a phthalocyanine unit was first synthesized and then a subphthalocyanine unit was formed (Scheme 13). The synthesis of Pc-subPc was carried out as follows. First, A3B type diiodophthalocyanine 36 was

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• . In contrast to the nucleophilic dimethoxycarbene, the formal transfer of the bis(carbomethoxy)carbene from the sulfur ylide 12 to E-1a leads to the cyclopropane derivative 13 [23] (Scheme 4). The reaction was proposed to occur stepwise via the zwiterrionic intermediate 14. Another example of a

• cyclobutanes 26 [20] (Scheme 7). The ratio of the isomers was the same irrespective of the configuration of 1b, indicating a stepwise reaction mechanism. Non-concerted [2 + 2]-cycloadditions were reported to occur between E- and Z-1b and bicyclo[2.1.0]pentene (27) [32]. Whereas in the case of E-1b two

• isomeric homo-Diels–Alder adducts were found in the mixture. [3 + 2]-Cycloadditions (1,3-dipolar cycloadditions) Electron-rich 1,3-dipoles such as thiocarbonyl S-methanides and azomethine ylides react with dipolarophiles E-1 and Z-1 to give five-membered cycloadducts through stepwise zwitterionic reaction

The effect of milling frequency on a mechanochemical organic reaction monitored by in situ Raman spectroscopy

• Patrick A. Julien,
• Ivani Malvestiti and
• Tomislav Friščić

Beilstein J. Org. Chem. 2017, 13, 2160–2168, doi:10.3762/bjoc.13.216

• spectroscopy [30] or by a tandem technique combining these two techniques [31]. Whereas valuable mechanistic information on the course of a milling reaction can be obtained through stepwise, ex situ monitoring [32] based on periodically interrupting the milling process followed by sample extraction and

• , primary assessment of the intensity of the milling process, and it affects the overall impact force, number and rate of impacts of milling media, as well as associated frictional heating. Raman spectroscopy was recently utilized for a stepwise, ex situ assessment of the effect of milling frequency on the

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• ]. Kusumoto et al. clearly demonstrated the advantage of the molecular clamping in application to the synthesis of α-cyclodextrin (Scheme 6) [51]. The tethering was used to improve the selectivity during the stepwise chain elongation via the coupling of maltose building blocks 21 and 22, as well as the

Grip on complexity in chemical reaction networks

• Albert S. Y. Wong and
• Wilhelm T. S. Huck

Beilstein J. Org. Chem. 2017, 13, 1486–1497, doi:10.3762/bjoc.13.147

• impossible, to solve without the reduction of variables [99]. To avoid loss in chemical information, we implemented the full set of rate equations in MATLAB and COPASI that could simulate the trajectory of the individual species by the stepwise numerical integration in time. Importantly, all rate constants

• perspective, however, urges an approach using a synthetic strategy based on the stepwise build-up of complex molecular systems. We envision the development of a toolbox that allows us to go beyond describing and understanding systems, extending to the rational design of function arising from a collection of

Synthesis of oligonucleotides on a soluble support

• Harri Lönnberg

Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134

• strategy may be utilized, but the stepwise linear approach proceeding from the 3´- to the 5´-terminus of ON is nowadays almost exclusively exploited [1][2]. The coupling reaction may take place either at oxidation level III or V of phosphorus. Owing to higher reactivity of P(III) centers, appropriately

• DCM/Et2O. In spite of several precipitations and recrystallizations, one coupling cycle could be completed in 5 hours, the stepwise coupling yield ranging from 90% to 95% and the crude PEG-bound octamer was obtained in 79% yield. The coupling of dGibu proceeded, however, in more than 100% yield, which

• building blocks, and the coupling was carried out in a mixture of pyridine and dioxane in the presence of NMI (5 equiv). Otherwise, the protocol was similar to the previous one. The average stepwise coupling yield upon the assembly of octamer d(5´-TAGCGCTA-3´) was 93.5%, and 55% of the PEG-anchored

Aqueous semisynthesis of C-glycoside glycamines from agarose

• Juliana C. Cunico Dallagnol,
• Alexandre Orsato,
• Diogo R. B. Ducatti,
• Miguel D. Noseda,
• Maria Eugênia R. Duarte and
• Alan G. Gonçalves

Beilstein J. Org. Chem. 2017, 13, 1222–1229, doi:10.3762/bjoc.13.121

• , there is no available methodology to obtain this building block using chemical hydrolysis. We produced compound 9 by hydrolysis of the previously synthesized glycamine 7. In addition, we conducted a stepwise sequence of hydrolysis and reduction reactions, followed by periodate cleavage of the 1,2

From chemical metabolism to life: the origin of the genetic coding process

• Antoine Danchin

Beilstein J. Org. Chem. 2017, 13, 1119–1135, doi:10.3762/bjoc.13.111

• this intelligent way, but unfolded more slowly. The actual emergence of the genetic code required a succession of small steps involving progressive improvement of peptide-based metabolism. As expected from a stepwise development, this process created a fair number of anecdotal features that were

Aggregation behaviour of a single-chain, phenylene-modified bolalipid and its miscibility with classical phospholipids

• Simon Drescher,
• Vasil M. Garamus,
• Christopher J. Garvey,
• Annette Meister and
• Alfred Blume

Beilstein J. Org. Chem. 2017, 13, 995–1007, doi:10.3762/bjoc.13.99

• again several peaks: the most distinct ones at 52.1 °C, and three smaller ones at 53.9 °C, 47.8 °C, and 40.2 °C. In the DSC heating curve of some of our bolalipid/phospholipid mixtures, an additional exothermic peak as well as a continuous or stepwise decrease in the heat capacity is observed during

Pd- and Cu-catalyzed approaches in the syntheses of new cholane aminoanthraquinone pincer-like ligands

• Nikolay V. Lukashev,
• Gennadii A. Grabovyi,
• Dmitry A. Erzunov,
• Alexey V. Kazantsev,
• Gennadij V. Latyshev,
• Alexei D. Averin and
• Irina P. Beletskaya.

Beilstein J. Org. Chem. 2017, 13, 564–570, doi:10.3762/bjoc.13.55

• +, Fe2+, Co2+, Ni2+, Zn2+, Cu2+, Ag+, Pb2+, Hg2+, Cr3+, Ga3+, Y3+, In3+) on the UV spectrum of 5c (Figure 2). The qualitative selectivity test by stepwise addition of 1, 2, 3, and 5 equiv of metal perchlorates in MeCN to the solution of 5c in MeCN revealed that the majority of cations did not influence

Fast and efficient synthesis of microporous polymer nanomembranes via light-induced click reaction

• Qi An,
• Youssef Hassan,
• Xiaotong Yan,
• Peter Krolla-Sidenstein,
• Tawheed Mohammed,
• Mathias Lang,
• Stefan Bräse and
• Manuel Tsotsalas

Beilstein J. Org. Chem. 2017, 13, 558–563, doi:10.3762/bjoc.13.54

• the substrates with an alkyne terminated self-assembled monolayer, which presents initial groups for the stepwise growing of the CMPs using the TYC reaction. In the first step, we immersed the functionalized surface in a solution of the tetra-topic thiol building block (tetrakis(4-sulfanylphenyl

Dimerization reactions of aryl selenophen-2-yl-substituted thiocarbonyl S-methanides as diradical processes: a computational study

• Michael L. McKee,
• Grzegorz Mlostoń,
• Katarzyna Urbaniak and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 410–416, doi:10.3762/bjoc.13.44

• , Winterthurerstrasse 190, CH-8057 Zurich, Switzerland 10.3762/bjoc.13.44 Abstract An intriguing stepwise diradical mechanism of the dimerization of the reactive intermediate (thiocarbonyl S-methanide) appearing in the reaction of phenyl selenophen-2-yl thioketone with diazomethane was studied by means of

• processes have not been studied in detail yet. Whereas the formation of the 1,3-dithiolane 4 can be explained via a concerted [2 + 3] cycloaddition of 1 as a 1,3-dipole with the activated C=S bond of 1, the dimerization leading to 5 seems to occur stepwise via an intermediate stabilized 1,6-diradical 6. In

• isolated from the reaction mixture. Thus, the presence of the heteroatom is of crucial importance for this new type of dimerization of aryl/hetaryl thiocarbonyl S-methanides of type 1 and this fact reflects the importance of so called ‘heavy atom effect’ [15] in the studied system. Stepwise, diradical

Spectral and DFT studies of anion bound organic receptors: Time dependent studies and logic gate applications

• Srikala Pangannaya,
• Neethu Padinchare Purayil,
• Shweta Dabhi,
• Venu Mankad,
• Prafulla K. Jha,
• Satyam Shinde and
• Darshak R. Trivedi

Beilstein J. Org. Chem. 2017, 13, 222–238, doi:10.3762/bjoc.13.25

• the aforementioned color change. The stepwise addition of Hg2+ ions to a solution of R1 leads to an increased intensity and bathochromic shift by 8 units of the absorption band at 266 nm. On the other hand the intensities of the bands centered at 325 nm and 395 nm decreased due to the deprotonation of

Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• + 3] total synthesis approach prompted us to retreat to the linear avenue (Scheme 1, route B) towards the target oligosaccharide in order to avoid the sterically demanding late-stage glycosylation. Differentially protected mannosazide 4 served as the starting point for stepwise assembly from the

Self-optimisation and model-based design of experiments for developing a C–H activation flow process

• Alexander Echtermeyer,
• Yehia Amar,
• Jacek Zakrzewski and
• Alexei Lapkin

Beilstein J. Org. Chem. 2017, 13, 150–163, doi:10.3762/bjoc.13.18

• algorithm to account for feasible and infeasible solutions in X, hence learning the promising regions of the design space and evolving some internal process knowledge stepwise with each new iteration. An infeasible solution could occur if an experiment fails in the laboratory. Thus, each point in the

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

• Pavel Nagorny and
• Zhankui Sun

Beilstein J. Org. Chem. 2016, 12, 2834–2848, doi:10.3762/bjoc.12.283

• with significantly lower ee (11%) was observed. These results suggest that the reaction might proceed mainly in a stepwise SN1-like manner, via a benzylic carbocation intermediate. Despite the fact that several variants of chiral halogen bond-donor catalysts have been synthesized, to the best of our

cis-Diastereoselective synthesis of chroman-fused tetralins as B-ring-modified analogues of brazilin

• Dimpee Gogoi,
• Runjun Devi,
• Pallab Pahari,
• Bipul Sarma and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2016, 12, 2816–2822, doi:10.3762/bjoc.12.280

• that the [6,5]-ring system in brazilin and related natural products 1–4 remains cis-fused, its corresponding [6,6]-ring system in 5 can have cis or trans stereochemistry at the ring junction. In our previous work, we observed a cis relationship (both in concerted or/and stepwise-epoxide ring opening

• ) between the 4-aryl group and H atom at the C-3 position of 4-arylchroman-3-ols (thus giving rise to trans-4-arylchroman-3-ols) [22][23]. But it was not obvious how the planned IFCEA cyclization onto the pre-existing 6-membered ring, in case of stepwise-epoxide ring opening, would influence the product

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

• Donghui Pan,
• Yanbin Wang and
• Guomin Xiao

Beilstein J. Org. Chem. 2016, 12, 2443–2449, doi:10.3762/bjoc.12.237

• generated in situ was reduced by stepwise addition of H2O2, which would improve the selectivity of 2a by preventing the side reactions. Next, the bromination of other para-xylene derivatives under optimized conditions (see Table 1, entry 11) were investigated to examine the versatility of the protocol. As