Epoxy resin thermosets (ERTs) are an important class of polymeric materials. However, owing to their highly cross-linked nature, they suffer from poor recyclability, which contributes to an unacceptable level of environmental pollution. There is a clear need for the design of inherently recyclable ERTs that are based on renewable resources. We present the synthesis and closed-loop recycling of a fully lignocellulose-derivable epoxy resin (DGF/MBCA), prepared from dimethyl ester of 2,5-furandicarboxylic acid (DMFD), 4,4′-methylenebis(cyclohexylamine) (MBCA), and glycidol, which displays excellent thermomechanical properties (a glass transition temperature of 170°C, and a storage modulus at 25°C of 1.2 gigapascals). Notably, the material undergoes methanolysis in the absence of any catalyst, regenerating 90% of the original DMFD. The diamine MBCA and glycidol can subsequently be reformed by acetolysis. Application and recycling of DGF/MBCA in glass and plant fiber composites are demonstrated.

Podophyllotoxin is probably the most prominent representative of lignan natural products. Deoxy‐, epi‐, and podophyllotoxin, which are all precursors to frequently used chemotherapeutic agents, were prepared by a stereodivergent biotransformation and a biocatalytic kinetic resolution of the corresponding dibenzylbutyrolactones with the same 2‐oxoglutarate‐dependent dioxygenase. The reaction can be conducted on 2 g scale, and the enzyme allows tailoring of the initial, “natural” structure and thus transforms various non‐natural derivatives. Depending on the substitution pattern, the enzyme performs an oxidative C−C bond formation by C−H activation or hydroxylation at the benzylic position prone to ring closure.

3,3-Bis(2,4,6-triisopropylphenyl)-1,1-binaphthyl-2,2-diyl hydrogenphosphate (TRIP) catalyzes the asymmetric allylation of aldehydes with organozinc compounds leading to highly valuable structural motifs, like precursors to lignan natural products. Our mechanistic proposal previously reported relies on two reaction intermediates and requires further investigation in order to really understand the mode of action and the origins of stereoselectivity. Detailed ab initio calculations, supported by experimental data, render a substantially different mode of action to the allyl boronate congener. Instead of a Brønsted acid based catalytic activation, the chiral phosphate acts as a counterion for the Lewis acidic zinc ion, which provides the activation of the aldehyde.

In this manuscript, we report on the formation and isolation of the di-nuclear rhenium(VI) µ-oxido bridged complex {[ReOCl₂(L1)]}₂(µ-O) (1), which we nick-named “deep purple” due to its intense purple color both in the solid state as well as in solution, and its surprising catalytic activity in oxyanion reduction. Complex 1 was obtained as the unintended product in an attempt to synthesize oxidorhenium(V) complex [ReOCl(L1)₂], using the O,N-bidentate phenol-dimethyloxazoline ligand HL1, equipped with two electron-donating tert-butyl groups on the phenol ring. Single crystal X-ray diffraction analysis finally revealed the surprising µ-oxido structure of 1, with two paramagnetic Re(VI) centers and a mixed cis/trans-chlorido arrangement on the two Re centers. Via a targeted synthesis in cyclohexane at 60 °C under ambient conditions, high yields of over 90% of 1 were obtained. To explain the source of the highly stereoselective formation of 1, its formation was examined by DFT calculations at the B3LYP-D3BJ/dhf-TZVPP@B3LYP-D3BJ/dhf-SVP level of theory, with solvent effects included via the COSMO model. In contrast to isoelectronic µ-oxido bridged Mo(V) complexes, 1 proved to be highly active in catalytic oxyanion reduction, namely perchlorate and nitrate reduction. With a catalyst loading of 5 mol% of 1, a conversion of 90% was observed for perchlorate. These findings highlight that in rhenium chemistry, µ-oxido bridged complexes like 1 still show promising catalyst activities for oxyanion reduction and potentially also other redox transformations.

Hydrogen is a primordial energy carrier and industrial raw material that will play a crucial role in future energy transition and de-fossilization ambitions. Silane hydrolysis represents an underexplored approach to hydrogen generation, yet most known systems have thus far focused on noble-metal catalysis. Herein we report a highly active transition metal-free method for the production of hydrogen from (sea)water and hydrosilanes, relying on the unique combination of simple bases as catalyst, and dimethyl sulfoxide as promoting solvent, assisted by mechanistic and computational studies. Remarkably, the hydrolysis of phenylsilane achieved a turnover frequency (TOF) of 5116 min–1, far superior to existing metal-free systems (TOF ≤ 8 min–1), and even surpassing noble-metal catalysts (TOF ≤ 170 min–1). The developed method rapidly generates hydrogen directly from seawater, applying polymethylhydrosilane (PMHS), a silicon industry waste, with rates up to 70.2 molH2/gcat/h. Notably, we have demonstrated the recyclability of the solvent, and re-use of the by-products formed during PMHS hydrolysis. Thus, the polysiloxane by-products were efficiently depolymerized into functional chlorosilane monomers, which are suitable for the design of new high-value silicon polymers. These findings highlight the broader applicability and circularity of our integrated approach.