Aromatic compounds serve as key feedstocks in the chemical industry, typically undergoing functionalization or full reduction. However, partial reduction via dearomative sequences remains underexplored despite its potential to rapidly generate complex three-dimensional scaffolds and the existing dearomative strategies often require metal-mediated multistep processes or suffer from limited applicability. Herein, a photocatalytic radical cascade approach enabling dearomative difunctionalization through selective spirocyclization/imination of nonactivated arenes is reported. The method employs bifunctional oxime esters and carbonates to introduce multiple functional groups in a single step, forming spirocyclic motifs and iminyl functionalities via N–O bond cleavage, hydrogen-atom transfer, radical addition, spirocyclization, and radical-radical cross-coupling. The reaction constructs up to four bonds (C−O, C−C, C−N) from simple starting materials. Its broad applicability is demonstrated on various substrates, including pharmaceuticals, and it is compatible with scale-up under flow conditions, offering a streamlined approach to synthesizing highly decorated three-dimensional frameworks.

Chiral and enantiopure perfluorinated sulfonimidamides act as low-molecular weight gelators at low critical gelation concentration (<1 mg mL-1) via supramolecular polymerization in nonpolar organic solvents and more heterogenic mixtures, such as biodiesel and oil. Freeze-drying of the organogel leads to ultralight aerogel with extremely low density (1 mg mL-1). The gelation is driven by hydrogen bonding resulting in a helical molecular ordering and unique fibre assemblies as confirmed by scanning electron microscopy, CD spectroscopy, and computational modeling of the supramolecular structure.

A combined experimental and theoretical investigation revealed mechanistic differences in the ring-opening polymerization (ROP) behavior of macrocyclic carbonates (MCs, 11-membered to 15-membered MCs). The study employs urea and potassium methoxide as the catalytic system for ROP. Besides the polymerization rate correlating with the ring size, where smaller rings have a faster polymerization rate, both the thermodynamic stability of the conformer and the stability of the transition state affect the polymerization rate. An experimental kinetic evaluation revealed a deviation between the polymerization rate of the 11-membered MC and the rest of the MCs. Computational investigation using density functional theory showed that the thermodynamic stability of the 11-membered MC differs from others, with a population distribution more toward the usually less energetically disfavored (E,Z)conformer, while the larger rings showed a preference for the Z,Z-conformation. In the transition state, the (E,Z)-conformer was found to be lower in energy compared to the (Z,Z)-conformation, which leads to a lower Gibbs free energy of activation for nucleophilic attack on the (E,Z)-conformation (Delta G(+/-) = 18.3 kcal center dot mol(-1)) compared to macrocycles with the more stable (Z,Z)-conformation (19.8 kcal center dot mol(-1)). The rate-determining step for the 11-membered MC with (E,Z)-conformation relates to the nucleophilic addition, while the rate-limiting step for the larger 15-membered MC corresponds to the ring-opening step. Linking the thermodynamic conformer stability of cyclic monomers to their inherent polymerization behavior is essential for the future design of selective catalysts for ROP.

Photo-mediated radical dearomatization involving 5-exo-trig cyclizations has proven to be an important route to accessing spirocyclic compounds, whereas 6-exo-trig spirocyclization has been much less explored. In this work, a dearomative annulation cascade is realized through photoredox-mediated C-O bond activation of aromatic carboxylic acids to produce two kinds of spirocyclic frameworks. Mechanistically, the acyl radical is formed through oxidation of triphenylphosphine and subsequent C-O bond cleavage, followed by a 6-exo-trig cyclization/SET/protonation sequence to generate the spiro-chromanone products in an intramolecular manner. Furthermore, the protocol was extended to more challenging intermolecular tandem sequences consisting of C-O bond cleavage, radical addition to an alkene substrate, and 5-exo-trig cyclization to yield complex spirocyclic lactams. Photo-mediated radical dearomatization involving 5-exo-trig cyclizations has proven to be an important route to accessing spirocyclic compounds, whereas 6-exo-trig spirocyclization has been much less explored. Here, a dearomative annulation cascade is realized through a photoredox-mediated C-O bond activation of aromatic carboxylic acids to produce two kinds of spirocyclic frameworks, whereby the spirocyclizations are triggered by acyl radical formation from benzoic acids leading to spiro-chromanones via a direct intramolecular 6-exo-trig cyclization or spirocyclic lactams via an intermolecular addition/5-exo-trig cyclization cascade.

Nickel boride catalyst prepared in situ from NiCl2 and sodium borohydride allowed, in the presence of an aqueous solution of TEMPO-oxidized nanocellulose (0.01 wt%), the reduction of a wide range of nitroarenes and aliphatic nitro compounds. Here we describe how the modified nanocellulose has a stabilizing effect on the catalyst that enables low loading of the nickel salt pre-catalyst. Ni-B prepared in situ from a methanolic solution was also used to develop a greener and facile reduction of azides, offering a substantially lowered catalyst loading with respect to reported methods in the literature. Both aromatic and aliphatic azides were reduced and the protocol is compatible with a one-pot Boc-protection of the obtained amine yielding the corresponding carbamates. Finally, bacterial crystalline nanocellulose was chosen as a support for the Ni-B catalyst to allow an easy recovery step of the catalyst and its recyclability for new reduction cycles.

Sulfonimidamides (SIAs) and sulfoximines (SOIs) have attracted attention due to their potential in agriculture and in medicinal chemistry as bioisosteres of biologically active compounds, and new synthetic methods are needed to access and explore these compounds. Herein, we present a light-promoted generation of perfluorinated aromatic nitrenes, from perfluorinated azides, that subsequently are allowed to react with sulfinamides and sulfoxides, generating achiral and chiral SIAs and SOIs. One of the enantiopure SIAs was evaluated as a novel chiral auxiliary in Grignard additions to the imines yielding the product in up to 96:4 diastereomeric ratio.

Polyetherimide (PEI) was used for coating copper substrates via electrophoretic deposition (EPD) for electrical insulation. Different substrate preparation and electrical field application techniques were compared, demonstrating that the use of a pulsed voltage of 20 V allowed for the best formation of insulating coatings in the 2-6 mu m thickness range. The results indicate that pulsed EPD is the best technique to effectively coat conductive substrates with superior surface finish coatings that could pass a dielectric withstand test at 10 kV mm(-1), which is of importance within the EV automotive industry.

A protocol for stereoselective C-radical addition to a chiral glyoxylate-derived N-sulfinyl imine was developed through visible light-promoted photoredox catalysis, providing a convenient method for the synthesis of unnatural α-amino acids. The developed protocol allows the use of ubiquitous carboxylic acids as radical precursors without prior derivatization. The protocol utilizes near-stoichiometric amounts of the imine and the acid radical precursor in combination with a catalytic amount of an organic acridinium-based photocatalyst. Alternative mechanisms for the developed transformation are discussed and corroborated by experimental and computational studies.

A bifunctional amine/squaramide catalyst promoted direct aldol addition of an hydantoin surrogate to pyridine 2-carbaldehyde N-oxides to afford adducts bearing two vicinal tertiary/quaternary carbons in high diastereo- and enantioselectivity (d.r. up to >20:1; ee up to 98 %) is reported. Acid hydrolysis of adducts followed by reduction of the N-oxide group yields enantiopure carbinol-tethered quaternary hydantoin-azaarene conjugates with densely functionalized skeletons. DFT studies of the potential energy surface (B3LYP/6-31+G(d)+CPCM (dichloromethane)) of the reaction correlate the activity of different catalysts and support an intramolecular hydrogen-bond-assisted activation of the squaramide moiety in the transition state of the catalytic reaction.