Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

• Nils Clamor,
• Mattis Damrath,
• Thomas J. Kuczmera,
• Daniel Duvinage and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

• turnover of the desired reaction [35]. To mitigate this, using silver salts as iodide scavengers in the reaction was attempted but yielded none of the desired product (Table 1, entry 2). DMF as a solvent lowered the yield to 16% (Table 1, entry 3). Switching the catalyst system to Cu(OTf)2/glyme gave a

• optimized conditions in hand, the substrate scope was explored. The variations of amides are outlined in Scheme 2. Switching from valeramide to benzamide as a substrate gave a more advantageous yield of 85% of 2b. We tested para-substituted benzamides in the reaction to further assess the diversity of

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• charge separation in all-PSCs such as switching from p-type dominated behaviour of polymer Qx5 to n-type dominated behaviour of Q6, with no off state due to presence of free charge carriers in the latter case [21]. Besides optimizing polymer structures, side chain engineering, introduction of electron

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

• Feng Chen,
• Xiu-Hua Xu,
• Zeng-Hao Chen,
• Yue Chen and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

• of H2O were added to the reaction mixture [40] (Table 1, entry 6), but the addition of more water did not improve the reaction efficiency further (Table 1, entry 7). The structure of nickel catalysts played a significant role in the reaction efficiency. Switching the Ni catalyst to NiCl2(dtbbpy

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• products (e.g., 7) whereas irradiation with blue light (λ = 455 nm) provided disubstituted products 8 (Figure 5A). Additionally, adding a different trapping reagent before switching from green to blue light allows for a sequential and controlled substitution in a one-pot reaction (Figure 5B). 2,4,6

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• -ketimino esters 62 as potential electrophiles. The chiral phosphoric acid P21 catalyzed this process facilitating the formation of a quaternary stereocenter containing α-amino esters. Switching the solvent from non-polar to polar showed a regioselectivity shift to a C7 alkylation of the indole ring. The

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• lead to an increased interest of several researchers are: (i) the remote and simple switching tunability; (ii) the different possibilities by varying different parameters, including irradiation time, wavelength and intensity; and (iii) the clean and nonthreatening performance. In search of new organic

• scaffolds [11]. In particular, rotaxanes and pseudorotaxanes have led to a greater number of applications due to their inherent dynamics and the switching possibility through a rational design [12]. Thus, rotaxane-based materials have attracted the interest of the scientific community due to their enhanced

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• . Except lately, in 2020, Chen and group [82] reported a Pd/Cu-catalyzed regio- and stereoselective synthesis of C2-alkenylated pyridines starting from internal alkynes 84 and pyridinium salts in a stereodivergent manner (Scheme 17a). The interesting part of this work was the switching of the alkene

• through the trans-effect (Scheme 18). The trans-effect is the switching of the metal coordination between the π-ring system and the hetero-(nitrogen) atom of pyridine [84][85]. In comparison to coordination with nitrogen, which is strong in nature, the coordination with the ring is weaker and cleavable

Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups

• Ita Hajdin,
• Romana Pajkert,
• Mira Keßler,
• Jianlin Han,
• Haibo Mei and
• Gerd-Volker Röschenthaler

Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39

• surprise, the application of Rh2(OAc)4 did not lead to the desired product neither in dichloromethane nor in toluene (Table 1, entries 1 and 2). Switching the catalyst to copper(I) iodide in refluxing DCM, did not result in the formation of product 6a, as well (Table 1, entry 3). However, when CuI was used

Modern flow chemistry – prospect and advantage

• Philipp Heretsch

Beilstein J. Org. Chem. 2023, 19, 33–35, doi:10.3762/bjoc.19.3

• typically call for an optimized or even specifically designed reactor built, the modularity of flow reactor is vital for quick reconfiguration and switching between different reactions. This argument is particularly true when natural product synthesis is to be performed in continuous flow. The need for

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• an arrangement of ten columns with an automated system to facilitate solvent switching and column loading [98]. As the product is being trapped in one column, a secondary HPLC pump, which is monitored online, regenerates the previous column. However, in the example described, final offline

Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition

• Anaïs Rousseau,
• Guillaume Vincent and
• Cyrille Kouklovsky

Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143

• reaction. However, switching the solvent from THF to toluene afforded 21% of product 23 with CeCl3 as additive. It appeared that the solvent had more influence on the course of the reaction than the metal. Indeed, reaction between vinyl iodide and ketone with n-BuLi in toluene [32] without any additive

Polymer and small molecule mechanochemistry: closer than ever

• José G. Hernández

Beilstein J. Org. Chem. 2022, 18, 1225–1235, doi:10.3762/bjoc.18.128

• , ideas on how polymer mechanochemistry could bias small molecule reactions were instantaneously provided by Prof. Stephen Craig [15], which included the possibility to mechanically control catalytic cycles in the future by switching the state of reactants or catalysts. Some approximations to this

From amines to (form)amides: a simple and successful mechanochemical approach

• Federico Casti,
• Rita Mocci and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 1210–1216, doi:10.3762/bjoc.18.126

• ). Switching to sodium sulfate as a grinding additive significantly enhanced the reaction performance (Table 1, entries 3 and 4). At this stage, we wondered, if using a more efficient dehydrating agent would be mandatory for the reaction to occur. Therefore, we turned our attention toward p-tosylimidazole (p

Thermally activated delayed fluorescence (TADF) emitters: sensing and boosting spin-flipping by aggregation

• Ashish Kumar Mazumdar,
• Gyana Prakash Nanda,
• Nisha Yadav,
• Upasana Deori,
• Upasha Acharyya,
• Bahadur Sk and
• Pachaiyappan Rajamalli

Beilstein J. Org. Chem. 2022, 18, 1177–1187, doi:10.3762/bjoc.18.122

• sensitive to acidic protons. Hence, the exposure to acid and base vapors using trifluoroacetic acid (TFA) and triethylamine (TEA) led to solid-phase fluorescence switching with fatigue resistance. The current study demonstrates the role of the donor strength and size in tuning ΔEST in the aggregated state

• . Therefore, an appropriate molecular design to suppress π–π stacking should help to obtain a strong emission in solution as well as in the solid state. Solid-state organic emitters with reversible fluorescence switching are emerging for the sensing of pollutant acid vapor [21][22][23]. However, quickly

• detecting organic acid vapor at ambient conditions is challenging for solid-state detectors. Therefore, developing a solid-state emitter with reversible switching of the optical properties by external stimuli, such as acid and base vapors, is important. As per the recent literature, such sensors are being

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• simplifies the synthetic procedure; the multistep process can be performed in an electrochemical cell, with the potential switching off prior to the addition of nucleophiles (thiols in our case). Complexes 10–12 were obtained as pure diastereomers (a set of signals corresponding to the individual compound is

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• ). With the in-line analytical data in hand, it was clear that the sample loop volume was too low to reach steady-state conditions. By switching to a continuous operation mode, we realized that a residence time of around 3 hours was necessary to reach steady-state conditions and the yield improved

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• chemistry and information science. Keywords: heteroleptic complexation; information science; supramolecular catalysis; switching catalysis; systems chemistry; Introduction Supramolecular catalysis [1][2][3] for most chemists is associated with a catalytically active capsule providing either activating

• /disassembly The common modus operandi to set up switchable catalysis usually relies on systems that can be toggled between two (or more) distinct switching states within a molecule [104][105][106][107]. In contrast, supramolecular approaches allow the shuffling and reshuffling of components to switch ON/OFF

• manifold opportunities for switchable ON/OFF catalysis controlled by supramolecular interconversions. Switchable catalysis decided by an ensemble of communicating molecules, which act as an information system and control the switching states, remodels somehow the situation in a living cell, where a desired

Unexpected chiral vicinal tetrasubstituted diamines via borylcopper-mediated homocoupling of isatin imines

• Marco Manenti,
• Leonardo Lo Presti,
• Giorgio Molteni and
• Alessandra Silvani

Beilstein J. Org. Chem. 2022, 18, 303–308, doi:10.3762/bjoc.18.34

• most effectively, further promoting the conversion of the substrate. Other changes in reaction conditions, such as heating at 70 °C, increasing the amount of copper catalyst to 10 mol % and switching the copper salt from CuSO4 to the more soluble Cu(OTf)2, did not improve the yield significantly (Table

Regioselectivity of the S_EAr-based cyclizations and S_EAr-terminated annulations of 3,5-unsubstituted, 4-substituted indoles

• Jonali Das and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2022, 18, 293–302, doi:10.3762/bjoc.18.33

• regioselectivity switching in the SEAr-based cyclizations of 3,5-unsubstituted, 4-substituted indoles. In the course of their studies on chemospecific cyclization of α-carbonyl sulfoxonium ylides on aryls and heteroaryls, the Aïssa group in 2019 demonstrated hexafluoroisopropanol (HFIP)-promoted regioselective

• indole-derived phenylenediamines. Indole C5 regioselective intramolecular FC acylation of 4-substituted indoles. Catalyst-dependent regioselectivity switching in the cyclization of ethyl 2-diazo-4-(4-indolyl)-3-oxobutanoate. Indole C5 regioselective cyclization of α-carbonyl sulfoxonium ylides. Indole C5

Synthesis and late stage modifications of Cyl derivatives

• Phil Servatius and
• Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

• diastereomeric ratio were similar to the reaction with LDA. If the Boc-protected ester 8b was then treated with LHMDS under the same reaction conditions (Table 1, entry 3) surprisingly no conversion was observed at all. Switching the base back to LDA (Table 1, entry 4) gave similar results than before (Table 1

Synthesis and bioactivity of pyrrole-conjugated phosphopeptides

• Qiuxin Zhang,
• Weiyi Tan and
• Bing Xu

Beilstein J. Org. Chem. 2022, 18, 159–166, doi:10.3762/bjoc.18.17

• . Switching the ᴅ-phosphoserine in 4a and 4b by ʟ-phosphoserine (pS), creates 5a and 5b. ᴅ-Trialanine replaces triglycine in 2f–h to produce 6a–c, which should resist to proteases, such as polyglycine hydrolases [73], which are known to cleave at the glycine–glycine site. The addition of an arginine residue

Me₃Al-mediated domino nucleophilic addition/intramolecular cyclisation of 2-(2-oxo-2-phenylethyl)benzonitriles with amines; a convenient approach for the synthesis of substituted 1-aminoisoquinolines

• Krishna M. S. Adusumalli,
• Lakshmi N. S. Konidena,
• Hima B. Gandham,
• Krishnaiah Kumari,
• Krishna R. Valluru,
• Satya K. R. Nidasanametla,
• Venkateswara R. Battula and
• Hari K. Namballa

Beilstein J. Org. Chem. 2021, 17, 2765–2772, doi:10.3762/bjoc.17.186

• inefficient for this transformation under similar reaction conditions yielding the desired product only in 16% yield (Table 1, entry 3). Interestingly, a substantial improvement in the yield of the reaction was observed by switching to Me3Al in toluene at 110 °C, delivering 85% of the desired product in 8 h

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• azulene units in the polymer chain. The thin film made up of polymer 121, containing entirely 4,7-disubstituted azulene, showed a reversible and rapid color switching in an acidic environment. This paper presented an interesting strategy of tuning the property of a polymer by incorporating a varying

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

• the last decades, numerous stimuli-responsive polymers have been developed and investigated regarding their switching properties. In particular, thermoresponsive polymers, which form a miscibility gap with the ambient solvent with a lower or upper critical demixing point depending on the temperature

• thermoresponsive polymers with limited mobility focusing on UCST behavior and the possibilities for influencing their thermoresponsive switching characteristics. It comprises star polymers, micelles as well as polymer chains grafted to flat substrates and particulate inorganic surfaces. The elaboration of the

• physicochemical interplay between the architecture of the polymer assembly and the resulting thermoresponsive switching behavior will be in the foreground of this consideration. Keywords: lower critical solution temperature (LCST); responsive coating; smart material; thermoresponsive polymer; upper critical

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• biggest synthetic polysaccharide obtained to date (Scheme 15). Switching from a