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The Pd‐catalysed decarboxylative asymmetric allylic alkylation (DAAA) has been applied to the enantioselective synthesis of sterically hindered benzofuran‐3(2H)‐one‐derived α‐aryl‐β‐keto esters employing the (R,R)‐ANDEN phenyl Trost ligand. A range of substrates were synthesised, employing previously developed aryllead triacetate methodology to install various aryl groups. The resulting α‐aryl‐α‐allyl benzofuran‐3(2H)‐one DAAA products were obtained in moderate to high yields and in enantioselectivities of up to 96 % ee, with the best results observed for substrates containing a di‐ortho‐substitution pattern on the aryl ring as well as naphthyl‐containing substrates. [ABSTRACT FROM AUTHOR]

The article titled "Cover Feature: Asymmetric Synthesis of Quaternary α-Aryl Stereocentres in Benzofuran-3(2H)-Ones Using Decarboxylative Asymmetric Allylic Alkylation" was published in Chemistry - A European Journal. The cover image features the Samuel Beckett bridge and the Convention Centre Dublin, which will host the 9th EuChemS Congress in July 2024. The image also includes a chemistry scheme illustrating a racemic β‐keto allyl ester and two diastereomeric transition states. The article provides more information on this topic and can be accessed through the DOI: 10.1002/chem.202401738. [Extracted from the article]

Inspired by the rigidified architecture of 'picket‐fence' systems, we propose a strategy utilizing strain to impose intramolecular tension in already peripherally overcrowded structures leading to selective atropisomeric conversion. Employing this approach, tuneable shape‐persistent porphyrin conformations were acquired exhibiting distinctive supramolecular nanostructures based on the orientation of the peripheral groups. The intrinsic assemblies driven by non‐covalent bonding interactions form supramolecular polymers while encapsulating small molecules in parallel channels or solvent‐accessible voids. The developed molecular strain engineering methodologies combined with synthetic approaches have allowed the introduction of the pivalate units creating a highly strained molecular skeleton. Changes in the absorption spectrum indicated the presence of severe steric repulsions between the peripheral groups which were confirmed by single crystal X‐ray analysis. To release the steric strain introduced by the peripheral units, thermal equilibration strategies were used to selectively convert the most abundant atropisomer to the desirable minor one. [ABSTRACT FROM AUTHOR]

Hydroxide‐bridged high‐valent oxidants have been implicated as the active oxidants in methane monooxygenases and other oxidases that employ bimetallic clusters in their active site. To understand the properties of such species, bis‐μ‐hydroxo‐NiII2 complex (1) supported by a new dicarboxamidate ligand (N,N′‐bis(2,6‐dimethyl‐phenyl)‐2,2‐dimethylmalonamide) was prepared. Complex 1 contained a diamond core made up of two NiII ions and two bridging hydroxide ligands. Titration of the 1 e− oxidant (NH4)2[CeIV(NO3)6] with 1 at −45 °C showed the formation of the high‐valent species 2 and 3, containing NiIINiIII and NiIII2 diamond cores, respectively, maintaining the bis‐μ‐hydroxide core. Both complexes were characterised using electron paramagnetic resonance, X‐ray absorption, and electronic absorption spectroscopies. Density functional theory computations supported the spectroscopic assignments. Oxidation reactivity studies showed that bis‐μ‐hydroxide‐NiIII23 was capable of oxidizing substrates at −45 °C at rates greater than that of the most reactive bis‐μ‐oxo‐NiIII complexes reported to date. [ABSTRACT FROM AUTHOR]

A series of IrIII complexes, based on 1,10-phenanthroline featuring aryl acetylene chromophores, were prepared and investigated as triplet photosensitizers. The complexes were synthesized by Sonogashira cross-coupling reactions using a 'chemistry-on-the-complex' method. The absorption properties and luminescence lifetimes were successfully tuned by controlling the number and type of light-harvesting group. Intense UV/Vis absorption was observed for the IrIII complexes with two light-harvesting groups at the 3- and 8-positions of the phenanthroline. The asymmetric IrIII complex (with a triphenylamine (TPA) and a pyrene moiety attached) exhibited the longest lifetime. Red emission was observed for all the complexes in deaerated solutions at room temperature. Their emission at low temperature (77 K) and nanosecond time-resolved transient difference absorption spectra revealed the origin of their triplet excited states. The singlet-oxygen (1O2) sensitization and triplet-triplet annihilation (TTA)-based upconversion were explored. Highly efficient TTA upconversion ( ΦUC=28.1 %) and 1O2 sensitization ( ΦΔ=97.0 %) were achieved for the asymmetric IrIII complex, which showed intense absorption in the visible region ( λabs=482 nm, ϵ=50900 m−1 cm−1) and had a long-lived triplet excited state (53.3 μs at RT). [ABSTRACT FROM AUTHOR]