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A novel catalyst‐free approach to benzoannulated oxygen‐containing heterocycles from fluorinated oligophenylenes is reported. Unlike existing methods, the presented reaction does not require an oxygen‐containing precursor and relies on an external oxygen source, potassium tert‐butoxide, which serves as an O2− synthon. The radical nature of the reaction facilitates nucleophilic substitution even in the presence of strong electron‐donating groups and enables de‐tert‐butylation required for the complete annulation. Also demonstrated is the applicability of the method to introduce five‐, six‐, and seven‐membered rings containing oxygen, whereas multiple annulations also open up a short synthetic path to ladder‐type O‐heteroacenes and oligodibenzofurans., O‐heteroacenes are now available by a one‐step LOOP reaction by SET‐induced SNAr‐radical de‐tert‐butylation‐SNAr. tBuOK serves as a reliable oxygen atom source and O2− synthon, enabling synthesis of dibenzofuran, benzoxanthenes, and benzooxepines, and a range of longer ladder‐type O‐heteroacenes from fluorinated oligophenylenes.

Although a huge number of facile synthesis methods for nanoparticles (NPs) do exist, the products usually exhibit a distribution in particle size and shape. Thus, a separation step needs to be applied to adjust the particle properties according to the needs of the later application. Chromatography is a potentially scalable separation method which is well-established for separating molecules and promising for classifying NPs by size. Herein, we lay the foundations of particle chromatography by studying the separation of a C60/C70 fullerene mixture as well-defined particle probes using a pyrene-functionalized silica stationary phase. C60 fullerenes are perfect model particles as they are spherical, roughly 1 nm in diameter, interacting via van der Waals interactions only. First, we extract the Henry coefficients for C60 and C70 fullerenes from the elution behavior of the fullerene mixture. Using a particle-wall as well as particle-particle model for the van der Waals interaction potential, we determine the ...

Herein, we show that biradical character and appropriate distribution of spin density can be used for synthetic purposes. We demonstrate the rational domino annulation that includes dehydrative π-extension (DPEX) as the initiation step and subsequent oxidative electrocyclizations (EC) promoted by favorable localization of the unpaired electrons enabling up to four C-C bonds formed during the reaction. Contradicting to the Woodward-Hoffmann rules, the reaction proceeds at room temperature, whereas termination occurs when biradical character vanishes.

Herein, we present a modular approach to pristine angularly fused planar acenes. The approach includes the Pd-catalyzed fusion of several building blocks and implements a dehydrative π-extension (DPEX) reaction as a key step enabling facile access to diverse two-dimensional acenes. The scope was demonstrated on nine examples with up to quantitative yield.

By exposure of α-fluorinated benzophenones to McMurry reaction conditions, we have observed the remarkable formation of 9,10-diphenylanthracene derivatives. This unexpected transformation necessitates the cleavage of the exceptionally stable aromatic C-F bond under mild McMurry conditions. In this work, the condensation of several related fluorinated benzo- and acetophenones has been investigated, which allow us to propose a domino-like fusion mechanism for this unusual transformation. The scope and limitations of the fluorine-promoted benzophenone fusion are subsequently discussed.

Large polycyclic aromatic hydrocarbons (PAHs) containing pentagons represent an important class of compounds that are considered to be superior materials in future nano-electronic applications. From this perspective, the development of synthetic approaches to large PAHs and nanographenes (NGs) is a matter of great importance. In this context indenoannulation appears to be the most practical way to introduce pentagons into NGs. Here we report that alumina-mediated C-F bond activation is an attractive tool for the synthesis of non-alternant NGs bearing several pentagons. The unique nature of the reaction leads to a rather counter-intuitive outcome and allows considering each previous aryl-aryl coupling as a promoter of the following one, despite the continuous increase in the strain energy. Thus, the presented strategy combines both facile synthesis and significant yields for large nonalternant PAHs and NGs.