Daniel Werz

• Professor at Technische Universität Braunschweig

We report ring-opening reactions of donor–acceptor (D–A) cyclopropanes with a variety of five- and six-membered enolizable azaheterocyclic thiones, using Sc(OTf)3 as catalyst in dichloromethane. The majority of these systems reacted through nucleophilic S-attack at the donor position of the cyclopropane. 5-Mercapto-1,3,4-triazoles were shown to giv...

An established concept to create radical intermediates is photoexcitation of a catalyst to a higher energy intermediate, subsequently leading to a photoinduced electron transfer (PET) with a reaction partner. The known concept of consecutive photoinduced electron transfer (con‐PET) leads to catalytically active species even higher in energy by the...

A (3+3)‐cycloaddition to afford 2‐azabiyclo[3.1.1]heptanes was realized by reacting highly strained aryl bicyclo[1.1.0]butane (BCBs) carboxylates with tosylated aziridines. Under Sc(OTf)3 catalysis the transformation proceeded smoothly under mild conditions to the corresponding bicyclic products bearing at the bridgeheads of the embedded four‐membe...

An established concept to create radical intermediates is photoexcitation of a catalyst to a higher energy intermediate, subsequently leading to a photoinduced electron transfer (PET) with a reaction partner. The known concept of consecutive photoinduced electron transfer (con‐PET) leads to catalytically active species even higher in energy by the...

Diversely substituted dimethyl 2‐arylcyclopropane‐1,1‐dicarboxylates (DACD) react under mild conditions, at ambient temperature in the presence of catalytic scandium triflate, with enolizable 5‐meracaptotetrazoles. Most commonly, this yields the corresponding 1 : 1 adducts via insertion of the S‐atom into the strained C,C bond, leading to ring‐open...

Deuterated and tritiated analogs of drugs are valuable compounds for pharmaceutical and medicinal chemistry. In this work, we present a novel hydrogen isotope exchange reaction of drugs using non‐directed homogeneous Pd‐catalysis. Aromatic C−H activation is achieved by a commercially available pyridine ligand. Using the most convenient and cheapest...

This short review demonstrates how MO-theoretical considerations can support the tailor-made design of new dye scaffolds, specifically the recently introduced BOIMPY class of fluorophores. Starting with historical and structural foundations, the influence of canonical streptocyanines on the electronic features of diarylmethenes and rhodamines is ex...

Deuterated and tritiated analogs of drugs are valuable compounds for pharmaceutical and medicinal chemistry. In this work, we present a novel hydrogen isotope exchange reaction of drugs using non‐directed homogeneous Pd‐catalysis. Aromatic C–H activation is achieved by a commercially available pyridine ligand. Using the most convenient and cheapest...

The recently reported electrochemical, organo‐mediator enabled deuteration of styrenes, a reaction referred to as “electrochemical deuterium atom transfer”, differs mechanistically from reported direct electrochemical hydrogenations/deuterations only by a mediated, homogeneous SET to the substrates. By comparing direct vs. mediated processes in gen...

The recently reported electrochemical, organo‐mediator enabled deuteration of styrenes, a reaction referred to as “electrochemical deuterium atom transfer”, differs mechanistically from reported direct electrochemical hydrogenations/deuterations only by a mediated, homogeneous SET to the substrates. By comparing direct vs. mediated processes in gen...

A new type of functionalized BODIPY dyes is described. Utilizing an established procedure for Buchwald-Hartwig reactions, we have been able to convert -chloro BODIPYs to α-azo-BODIPYs using phenylhydrazines. Optimization of the reaction conditions and variation of the BODIPY core and the phenylhydrazine were conducted. Absorption and emission spec...

A convergent route towards nitrogen-bridged BODIPY oligomers has been developed. The synthetic key step is a Buchwald-Hartwig cross-coupling reaction of an alpha-amino-BODIPY and the respective halide. Not only does the selective synthesis provide control of the oligomer size, but the facile preparative procedure also enables easy access to this ty...

Invited for the cover of this issue are the groups of Holger Braunschweig at the Julius‐Maximilians‐Universität Würzburg, Germany and Eufrânio N. da Silva Júnior at the Universidade Federal de Minas Gerais, UFMG, Brazil. The image depicts the electrochemical synthesis of selenium‐containing BODIPY molecules with lightning symbolizing the electrifyi...

We report a rapid, efficient, and scope‐extensive approach for the late‐stage electrochemical diselenation of BODIPYs. Photophysical analyses reveal red‐shifted absorption – corroborated by TD‐DFT and DLPNO‐STEOM‐CCSD computations – and color‐tunable emission with large Stokes shifts in the selenium‐containing derivatives compared to their precurso...

Reactions of dimethyl 2‐arylcyclopropane‐1,1‐dicarboxylates, used as representatives of D‐A cyclopropanes, with tropothione were carried out in the presence of scandium triflate as a catalyst, under mild conditions (CH2Cl2 solution, rt). The anticipated (8+3)‐cycloaddition products, cycloheptatriene fused thiopyrans, were obtained in good to excell...

Deuterated and tritiated analogs of drugs are valuable compounds for pharmaceutical and medicinal chemistry. In this work, we present a novel hydrogen isotope exchange reaction of drugs using non-directed homogeneous Pd catalysis. Aromatic C–H activation is achieved by a commercially available pyridine ligand. Using the most convenient and cheapest...

Here, we present a new route to dyes of the BODIPY family. We first built up a N-Boc-protected dipyrromethene scaffold via an aminopalladation cascade. Subsequentially, the pyrrole moiety was deprotected...

Single electron redox processes allow the formation of highly reactive radicals – valuable intermediates that enable unique transformations in organic chemistry (1,2). An established concept to create radical intermediates is photoexcitation of a catalyst to a higher energy intermediate, subsequently leading to a photoinduced electron transfer (PET...

An electrochemical method for the synthesis of 3,3,5,5-tetrasubstituted 1,2-dioxolanes from donor-acceptor cyclopropanes with quaternary donor positions is described. This catalyst-free strategy delivers radical cations after C(sp3)-C(sp3) cleavage by direct anodic oxidation of the strained carbocycle. A broad scope with regard to the cyclopropanes...

A general method for 1,3-bisfunctionalization of donor-acceptor (D-A) cyclopropanes using sulfinate salts and electrophilic fluorination reagents is described. Utilizing Lewis acid catalysis, nucleophilic ring-opening by the sulfinate anion followed by trapping of electrophilic fluorine by the anionic intermediate leads to the formation of γ-fluoro...

We describe an operationally simple and user‐friendly protocol that allows the site‐selective hydrogenation and deuteration of di‐, tri‐ and tetrasubstituted benzylic olefins by electroreduction while other groups prone to hydrogenation are present. The radical anionic intermediates react with the most inexpensive hydrogen/deuterium source H2O/D2O....

A 1,3‐carbocarbonation of 2‐substituted cyclopropane 1,1‐dicarboxylates introduces various saturated or unsaturated carbon residues at the 1‐ and 3‐ position of the former three‐membered ring. Under copper catalysis, ring‐opening attack with a Grignard reagent proceeded smoothly; the intermediate was converted to the final product by reaction with...

Pseudaminic acid (Pse) is a significant prokaryotic monosaccharide found in important Gram‐negative and Gram‐positive bacteria. This unique sugar serves as a component of cell‐surface‐associated glycans or glycoproteins and is associated with their virulence. We report the synthesis of azidoacetamido‐functionalized Pse derivatives as part of a sear...

The noncovalent interactions betweena zides and oxygen-containing moieties are investigated through ac om-putational study based on experimental findings.T he targeted synthesis of organic compounds with close intramolecu-lar azide-oxygen contacts yielded six new representatives, for whichX-ray structures were determined. Twoo ft hose compounds wer...

A novel class of highly activated donor‐acceptor cyclopropanes bearing only a single, vinylogous acceptor is presented. These strained moieties readily undergo cycloadditions with aldehydes, ketones, thioketones, nitriles, naphth‐2‐ols and various other substrates to yield the corresponding carbo‐ and heterocycles. Diastereocontrol can be achieved...

The plasma membrane is a complex assembly of proteins and lipids that can self‐assemble in submicroscopic domains commonly termed “lipid rafts”, which are implicated in membrane signaling and trafficking. Recently, photo‐sensitive lipids were introduced to study membrane domain organization, and photo‐isomerization was shown to trigger the mixing a...

A novel class of highly activated donor‐acceptor cyclopropanes bearing only a single, vinylogous acceptor is presented. These strained moieties readily undergo cycloadditions with aldehydes, ketones, thioketones, nitriles, naphth‐2‐ols and various other substrates to yield the corresponding carbo‐ and heterocycles. Diastereocontrol can be achieved...

Chalcogen bonding has developed to become a crucial platform for numerous types of chemistry. While solid-state chemists apply such interactions to design and engineer crystals, chalcogen contacts are used in solution to establish powerful catalytic transformations and to track anion processes. In addition to the mentioned fields, this book chapter...

The Fujiwara-Moritani reaction is a powerful tool for the olefination of arenes by Pd-catalysed C-H activation. However, the need for superstoichiometric amounts of toxic chemical oxidants makes the reaction unattractive from an environmental and atom-economical view. Herein, we report the first non-directed and regioselective olefination of simple...

The Fujiwara-Moritani reaction is a powerful tool for the olefination of arenes by Pd-catalyzed C–H activation. However, the need for superstoichiometric amounts of toxic chemical oxidants makes the reaction unattractive from an environmental and atom-economical view. Herein, we report the first non-directed and regioselective olefination of simple...

A facile and efficient route to dithiolanes starting from donor-acceptor cyclopropanes is reported. Potassium p-toluenethiosulfonate has been established as the reagent of choice for this formal insertion of the disulfide moiety. Using this methodology, dithiolanes have been synthesized in moderate to good yields with high functional group toleranc...

The glycosphingolipid Gb3 is a specific receptor of the bacterial Shiga toxin (STx). Binding of STx to Gb3 is a prerequisite for its internalization into the host cells, and the ceramide's fatty acid of Gb3 has been shown to influence STx binding. In in vitro studies on liquid ordered (lo)/liquid disordered (ld) coexisting artificial membranes, Shi...

C-H deuteration has been intricately developed to satisfy the urgent need for site-selectively deuterated organic frameworks. Deuteration has been primarily used to study kinetic isotope effects of reactions but recently its significance in pharmaceutical chemistry has been discovered. Deuterium labelled compounds have stolen the limelight since th...

Herein we present a systematic study demonstrating to which extent exciton formation can amplify fluorescence based on a series of ethylene‐bridged oligo‐BODIPYs. A set of non‐ and weakly fluorescent BODIPY motifs was selected and transformed into discrete, chain‐like oligomers by linkage via a flexible ethylene tether. The prepared superstructures...

Herein we present a systematic study demonstrating to which extent exciton formation can amplify fluorescence based on a series of ethylene‐bridged oligo‐BODIPYs. A set of non‐ and weakly fluorescent BODIPY motifs was selected and transformed into discrete, chain‐like oligomers by linkage via a flexible ethylene tether. The prepared superstructures...

We report a simple, iterative strategy for the synthesis of [7]helicenes starting from substituted 1,4-xylene building blocks. In the first step, we take advantage of the deprotonatable methyl groups to achieve ethano-bridged dimers. These are oxidatively coupled (without using metal-containing catalysts or light) using a hypervalent iodine reagent...

A novel ring-opening reaction of donor-acceptor cyclopropanes through a one-pot three-component nucleophilic addition of amines, CS2, and D-A cyclopropanes has been described. New γ-dithiocarbamate dialkyl malonate skeletons were obtained in up to 97% yield.

Pd-catalysed C-H functionalisation of free carboxylic acids has drawn significant attention over the last few years due to the predominance of carboxylic acid moieties in pharmaceuticals and agrochemicals. But their coordinating ability was overlooked and masked by exogenous directing groups for a long time. Even other crucial roles of carboxylic a...

Donor-acceptor cyclopropanes (DACs) react with lithium alkynylselenolates in the presence of In(OTf)3 to furnish tetrahydroselenophenes with semicyclic double bonds. The reaction can be regarded as a formal insertion of selenoketenes...

Near-infrared (NIR) fluorophores are emerging tools for biophotonics because of their reduced scattering, increased tissue penetration and low phototoxicity. However, the library of NIR fluorophores is still limited. Here, we report the NIR fluorescence of two benzene-fused oligo-BODIPYs in their hexameric (H) and octameric (O) forms. These dyes em...

We present (3+2)‐ and (4+2)‐cycloadditions of donor–acceptor (D–A) cyclopropanes and cyclobutanes with N‐sulfinylamines and a sulfur diimide, along with a one‐pot, two‐step strategy for the formal insertion of HNSO2 into D–A cyclopropanes. These are rare examples of cycloadditions with D–A cyclopropanes and cyclobutanes whereby the 2π component con...

Alkyne aminopalladation reactions starting from tosylamides are reported. The emerging vinylic Pd species are converted either in an intramolecular Heck reaction with olefinic units or in an intermolecular Suzuki reaction by using boronic acids exhibiting broad functional group tolerance. Tetra(hetero)substituted tosylated enamines are obtained in...

We present (3+2)‐ and (4+2)‐cycloadditions of donor–acceptor (D–A) cyclopropanes and cyclobutanes with N‐sulfinylamines and a sulfur diimide, along with a one‐pot, two‐step strategy for the formal insertion of HNSO2 into D–A cyclopropanes. These are rare examples of cycloadditions with D–A cyclopropanes and cyclobutanes whereby the 2π component con...

The reactivity of donor‐acceptor (D‐A) cyclopropanes towards thioketenes was investigated. In a (3+2)‐cycloaddition using Sc(OTf)3 as a Lewis acidic catalyst, the corresponding exocyclic thioenol ethers (2‐methylidene tetrahydrothiophenes) were formed in moderate to good yields. Unsymmetrical thioketenes provided E/Z mixtures at the double bond, wi...

We describe a general electrochemical method to functionalize donor-acceptor (D-A) cyclopropanes and -butanes with arenes utilizing Friedel-Crafts-type reactivity. The catalyst-free strategy relies on the direct anodic oxidation of the strained carbocycles, which leads after C(sp3)-C(sp3) cleavage to radical cations that act as electrophiles for th...

We describe the first electrochemical activation of D–A cyclopropanes and D–A cyclobutanes leading after C(sp³)−C(sp³) cleavage to the formation of highly reactive radical cations. This concept is utilized to formally insert molecular oxygen after direct or DDQ‐assisted anodic oxidation of the strained carbocycles, delivering β‐ and γ‐hydroxy keton...

A series of distinct BODIPY heterooligomers (dyads, triads, and tetrads) comprising a variable number of typical green BODIPY monomers and a terminal red-emitting styryl-equipped species acting as an energy sink was prepared and subjected to computational and photophysical investigations in solvent media. An ethylene tether between the single monom...

Pseudaminic acid (Pse) is a significant prokaryotic monosaccharide found in important Gram‐negative and Gram‐positive bacteria. This unique sugar serves as a component of cell‐surface‐associated glycans or glycoproteins and is associated with their virulence. We report the synthesis of azidoacetamido‐functionalized Pse derivatives as part of a sear...

Despite the highly strained nature of cyclopropanes possessing three vicinal quaternary carbon stereocenters, the regio‐ and diastereoselective copper‐catalyzed carbomagnesiation reaction of cyclopropenes provides an easy and efficient access to these novel persubstituted cyclopropyl cores with a complete regio‐ and diastereoselectivity.

The first electrochemical activation of donor–acceptor (D–A) cyclopropanes and D–A cyclobutanes has been applied for the formal insertion of molecular oxygen into these compounds. C(sp³)−C(sp³) cleavage of the ring moieties was achieved either by direct anodic electrolysis or by utilizing a DDQ-assisted electrochemical strategy. Quantum-chemical ca...

Despite the highly strained nature of cyclopropanes possessing three vicinal quaternary stereocenters, the regio‐ and diastereoselective copper‐catalyzed carbomagnesiation reaction provides an easy and efficient access to these novel persubstituted cyclopropyl cores with a complete regio‐ and diastereoselectivity. Abstract Despite the highly strai...

A range of unprocessed, reducing sugar substrates (mono‐, di‐, and trisaccharides) is shown to take part in a straightforward four‐step synthetic route to water‐soluble, uncharged BODIPY derivatives with unimpaired chiral integrity and high fluorescence efficiency. A wide compatibility with several postfunctionalizations is demonstrated, thus sugge...

ConspectusDonor-acceptor (D-A) cyclopropanes have gained increased momentum over the past two decades. The use of these highly strained three-membered entities paved the way to innovative and original transformations yielding complex cyclic and acyclic architectures that otherwise might be difficult to address. Since the fundamentals were laid by W...

We propose a new concept of the triple role of protic ionic liquids with nucleophilic anions: a) a regenerable solvent, b) a Brønsted acid inducing diverse transformations via general acid catalysis, and c) a source of a nucleophile. The efficiency of this strategy was demonstrated using thiocyanate‐based protic ionic liquids for the ring‐opening o...

We present a Lewis acid catalyzed nucleophilic ring‐opening of donor‐acceptor cyclopropanes and ‐butanes by sydnones, utilizing their respective 1,3‐ and 1,4‐reactivity. The same conditions can be applied for the addition of sydnones to Michael acceptors. We propose a Friedel‐Crafts like mechanism. The reaction provides a rare, low‐temperature, tra...

An easy and efficient route to obtain 2-amino-4,5-dihydrothiophenes is presented. A formal (3+2)-cycloaddition of donor-acceptor cyclopropanes and ammonium thiocyanate catalyzed by Yb(OTf)3 delivers the desired products in good to excellent yields. A broad range of functional groups is tolerated during this process.

Twelve sugars, differing in size and stereochemistry, were used as building blocks in a modular, efficient four‐step synthetic route to multifunctional BODIPY glycoconjugates with high fluorescence and hydrophilicity. The chiral information was transferred unchanged, thereby providing complex and distinct probes for target‐oriented binding studies...

We report the improved direct access to red-emitting BOIMPY fluorophores (λ ≈ 600 nm) via a simple one-pot approach. Our method starts from easily available benzimidazole-2-carboxylic acids and not only greatly improves the overall yields but also saves both costly reagents and time. In addition, the method facilitates the synthesis of novel unsymm...

A resplendent trio: Protic ionic liquids (PILs) with nucleophilic anions served in concert as regenerable reaction medium, Brønsted acid, and a source of nucleophile. Heating of donor–acceptor cyclopropanes with 1‐methylimidazolium thiocyanate (B:⋅HNCS) afforded products of formal (3+2)‐ and (4+2)‐cycloaddition of isothiocyanic acid. Abstract We p...

Allylation reactions are one of the most fundamental and productive C-C bond-forming transformations, as the allyl group can provide a useful handle for further manipulation. Apart from this, their omnipres- ence in bioactive species makes them invaluable in medicinal science and pharmaceutical industries. Pioneered by Tsuji and Trost, a myriad of...

We present a straightforward, three‐step synthesis engaging an oligomerization and subsequent one‐pot oxidation step to form fully conjugated, benzene‐fused oligo‐BODIPYs from simple BODIPY precursors. FeCl3 serves as an efficient, bifunctional oxidant for a (multiple) cyclization/desaturation process, applied to ethylene‐bridged dimeric, trimeric...

Einfach erhältliche, ethylenverbrückte Oligo‐BODIPY‐Vorstufen verschiedener Größen dienen als exzellente Substrate für eine vielstufige Eintopf‐Oxidationssequenz mit FeCl3, um benzanellierte Produkte als vollständig durchkonjugierte, halbkreisförmige und luftstabile Nahinfrarot‐Farbstoffe mit interessantem Reduktionsverhalten zu erhalten. Abstract...

Gb3 glycosphingolipids are the specific receptors for bacterial Shiga toxin. Whereas the trisaccharidic head group of Gb3 defines the specificity of Shiga toxin binding, the lipophilic part composed of sphingosine and different fatty acids is suggested to determine its localization within membranes impacting membrane organisation and protein bindin...

Chalcogen Bonding beschreibt die Wechselwirkung von Lewis‐sauren Chalkogen‐Atomen mit verschiedenen Lewis‐basischen Einheiten. Dieser Viewpoint zeichnet die Entwicklung des Begriffs von seinem Vorgänger „Chalkogen‐Chalkogen‐Wechselwirkungen“ nach und diskutiert verschiedene faszinierende Bereiche der chemischen Forschung, die durch dieses Phänomen...

In this work, the influence of the rigid substrate on the determination of the sample Young's modulus, the so‐called bottom‐effect artifact, is demonstrated by an atomic force microscopy force‐spectroscopy experiment. The nanomechanical properties of a one‐component supported lipid membrane (SLM) exhibiting areas of two different thicknesses are st...

Starting from readily available o‐diazoacyl‐substituted arene carboxylates, scaffolds with the 5,9‐epoxycyclohepta[b]pyran‐2(3H)‐one core were obtained by cooperative RhII, Lewis and Brønsted acid catalysis. Four new bonds, three functional groups (lactone, ketal, and alcohol) and four contiguous stereocenters are formed during this regio‐ and dias...

The intra- and intermolecular synthesis of selenium-substituted acyclic and heterocyclic acrylonitrile derivatives is presented. The 1,2-difunctionalization of several internal alkynes substituted not only by aliphatic and aromatic residues but also by heteroelements is realized by the Pd-catalyzed activation of aromatic and aliphatic selenocyanate...

The two lectins LecA from Pseudomonas aeruginosa and the B-subunit of Shiga toxin from Shigella dysenteriae (StxB) share the glycosphingolipid globotriaosylceramide (Gb3) as receptor. Counterintuitively, we found that LecA and StxB segregated into different domains after recognizing Gb3 at the plasma membrane of cells. We hypothesized that the orie...

Ferrocenyl thioketones reacted with donor–acceptor cyclopropanes in dichloromethane at room temperature in the presence of catalytic amounts of Sc(OTf) 3 yielding tetrahydrothiophene derivatives, products of formal [3 + 2]-cycloaddition reactions, in moderate to high yields. In all studied cases, dimethyl 2-arylcyclopropane dicarboxylates reacted w...

An intramolecular palladium‐catalyzed trans‐carbocarbonation cascade is presented that consists of a formal anti‐carbopalladation of an internal carbon‐carbon triple bond terminated by a Suzuki cross‐coupling reaction. The key to success in obtaining the anti‐geometry of the emerging double bond is the use of alkyne units with substituents that avo...

A general and efficient strategy for synthesis of tri‐, hexa‐ and heptasaccharidic substructures of the lipopolysaccharide of Providencia rustigianii O34 is described. For the heptasaccharide seven different building blocks were employed. Special features of the structures are an α‐linked galactosamine and the two embedded α‐fucose units, which are...

The reactivity of donor–acceptor (D–A) cyclopropanes towards acceptor‐substituted ketenedithioacetals was investigated. In a Lewis‐acid‐catalyzed (3+2)‐cycloaddition, the corresponding dithiaspiro compounds were synthesized in good yields. The 1,3‐dithiane unit, a masked keto functionality, was cleaved by N‐iodosuccinimide. Thus, this two‐step proc...

Ferrocenyl thioketones react with donor-acceptor cyclopropanes in dichloromethane at room temperature in the presence of catalytic amounts of Sc(OTf) 3 yielding tetrahydrothiophene derivatives, products of formal (3+2)-cycloaddition reactions, in moderate to high yields. In all studied cases, dimethyl 2-arylcyclopropane dicarboxylates react with co...

Internal alkynes substituted by aliphatic or aromatic moieties or by heteroatoms were converted into sulphur-substituted acrylonitrile derivatives. Key is the use of Pd catalysis, which allows the addition of aromatic and aliphatic thiocyanates in an intra- and intermolecular manner. Substrates with several alkyne units underwent further carbopalla...

Arynes and donor–acceptor (D–A) cyclopropanes are two classes of strained systems having the potential for numerous applications in organic synthesis. The last two decades have witnessed a renaissance of interest in the chemistry of these species primarily because of the mild and robust methods for their generation or activation. Commonly, arynes a...

A palladium-catalyzed intramolecular formal anti-carboamination of internal alkynes for the synthesis of tetrasubstituted enamines and pyrroles is reported. A broad range of different aniline derivatives, and also alkylated and benzylated amines, were used for the termination of the cascade. In the follow-up chemistry, we demonstrate that the TBS-p...

A general approach is described for the formation of tetrahydrothiepines using donor-acceptor cyclopropanes. Thiochalcones, functioning as sulfur-containing four-atom building blocks, were reacted in a Lewis acid catalyzed formal (4 + 3)-cycloaddition reaction with donor-acceptor cyclopropanes as three-atom building blocks. Under mild conditions va...

The receptor lipid Gb3 is responsible for the specific internalization of Shiga toxin (STx) into cells. The head group of Gb3 defines the specificity of STx binding, and the backbone with different fatty acids is expected to influence its localization within membranes impacting membrane organization and protein internalization. To investigate this...

Das Unsichtbare sichtbar machen: Shigatoxin‐B‐Untereinheiten (STxB) binden an flüssig‐geordnete Domänen in Modellmembranen, was darauf hindeutet, dass ihr Gb3‐Rezeptor in diesen Domänen lokalisiert ist. Der synthetische Zugang zu Gb3‐Glykosphingolipiden mit markierten Kopfgruppen ermöglicht die Quantifizierung ihrer Verteilung in riesigen unilamell...

Zwei Seiten ein‐ und derselben Medaille? Arine und Donor‐Akzeptor‐Cyclopropane zeigen auffallende Ähnlichkeiten in ihrer Reaktivität. Dieser Kurzaufsatz zielt darauf ab, Parallelen bei Insertionen und Anellierungen dieser beiden gespannten Systeme aufzuzeigen. Abstract Arine und Donor‐Akzeptor‐substituierte (D‐A‐)Cyclopropane sind zwei Klassen ges...

A 1,3‐aminothiolation was realized by reacting 2‐substituted cyclopropane 1,1‐dicarboxylates with sulfonamides and N‐(arylthio)succinimides. Under Sn(OTf)2 catalysis the transformation proceeded smoothly to the corresponding ring‐opened products bearing the sulfonamide in the 1‐position next to the donor and the arylthio residue in the 3‐position n...

Donor-acceptor (D-A) cyclobutanes with two geminal ester groups as acceptors are reacted with electron-rich arenes as nucleophiles to afford ring-opened products. AlCl3 mediates this Friedel-Crafts-type reaction. A variety of donors and electron-rich arenes are used. Nucleophilic thiols and selenols also trigger this ring-opening reaction. Furtherm...

The development of efficient and mild methods for the synthesis of organofluorine compounds is of foremost interest in various fields of chemistry. A direct pyrimidine‐based selective meta‐C−H perfluoroalkenylation of arenes involving several commercially available perfluoroolefins is described. The synthetic versatility of the protocol is demonstr...

Novel dyes based on extended fulvene motifs are reported. The carbon skeleton was generated by a catalyzed addition of donor–acceptor cyclopropanes to naphthoquinone. The hydroxy group at the central ring of the tricyclic fulvene motif was converted into the triflate, which reacted efficiently with a wide range of nucleophiles, resulting in substit...