Abstract:

A Pd catalyst made from a Pd(0) source and a bulky biaryl phosphine ligand promotes highly efficient intramolecular (3 + 2) heterocycloadditions between alkylidenecyclopropanes (ACPs) and carbonyls. The annulations provide a straightfor-ward access to fused polycyclic systems featuring β-methylene tetrahydrofuran moieties. DFT data support a pallada-ene process and shed light on the critical role of hemilabile interactions between the Pd center and the bulky biaryl phosphine. Significantly, these Pd(0) catalysts are also effective for promoting intermolecular formal cycloadditions between ACPs and trifluoromethyl ketones, thus providing for a direct entry to chiral THFs bearing trifluoromethyl–substituted carbons

External link: https://pubs.acs.org/doi/10.1021/acscatal.0c01827

Abstract: The generation of catalytically active metalloproteins inside living mammalian cells is a major research challenge at the interface between catalysis and cell biology. Herein we demonstrate that basic domains of bZIP transcription factors, mutated to include two histidine residues at i, i+4 positions, react with palladium (II) sources to generate catalytically active, stapled pallado‐miniproteins. The resulting constrained peptides are efficiently internalized into living mammalian cells, where they can perform palladium‐promoted depropargylation reactions, without cellular fixation. Control experiments confirm the requirement of the peptide scaffolding and the palladium staple for attaining the intracellular reactivity.

External link: https://onlinelibrary.wiley.com/doi/10.1002/anie.202002032

Abstract:

When nanoparticles (NPs) are exposed to biological media, proteins are adsorbed, forming a so-called protein corona (PC). This cloud of protein aggregates hampers the targeting and transport capabilities of the NPs, thereby compromising their biomedical applications. Therefore, there is a high interest in the development of technologies that allow control over PC formation, as this would provide a handle to manipulate NPs in biological fluids. We present a strategy that enables the reversible disruption of the PC using external stimuli, thereby allowing a precise regulation of NP cellular uptake. The approach, demonstrated for gold nanoparticles (AuNPs), is based on a biorthogonal, supramolecular host–guest interactions between an anionic dye bound to the AuNP surface and a positively charged macromolecular cage. This supramolecular complex effectively behaves as a zwitterionic NP ligand, which is able not only to prevent PC formation but also to disrupt a previously formed hard corona. With this supramolecular stimulus, the cellular internalization of AuNPs can be enhanced by up to 30-fold in some cases, and even NP cellular uptake in phagocytic cells can be regulated. Additionally, we demonstrate that the conditional cell uptake of purposely designed gold nanorods can be used to selectively enhance photothermal cell death.

External link: https://twitter.com/MetBioCat/status/1235837116090691585

Starting this brand new 2020 year... we are glad to announce our most recent publication at ACS Catalysis journal, entitled "Palladium-catalyzed formal (4+2) cycloaddition between alkyl amides and dienes initiated by the activation of C(sp3)−H bonds" and authored by B. Cendón, M. Font, J. L. Mascareñas and M. Gulías, is already available as just accepted manuscript.

External link: https://twitter.com/MetBioCat/status/1230768577738764290