The direct conversion of aliphatic carboxylic acids to the corresponding alkyl fluorides has been achieved via visible light-promoted photoredox catalysis. This operationally simple, redox-neutral fluorination method is amenable to a wide variety of carboxylic acids. Photon-induced oxidation of carboxylates leads to the formation of carboxyl radicals, which upon rapid CO2-extrusion and F• transfer from a fluorinating reagent yield the desired fluoroalkanes with high efficiency. Experimental evidence indicates that an oxidative quenching pathway is operable in this broadly applicable fluorination protocol.

Herein, the use of a well-defined low-valent cobalt(I) catalyst [HCo(PMe3)4] capable of performing the highly regio- and stereoselective hydrosilylation of internal alkynes is reported. The reaction can be applied to a variety of hydrosilanes, symmetrical and unsymmetrical alkynes, giving in many cases a single hydrosilylation isomer. Experimental and theoretical studies suggest the key step to be a hydro-cobaltation and that the reaction proceeds through a classical Chalk-Harrod mechanism.

International audienceA simple hydrido-cobalt complex efficiently catalyses the highly regio- and stereoselective dimerisation of various terminal arylacetylenes under mild conditions. The corresponding (E)-1,4-enynes are obtained as sole isomers with good to excellent yields. DFT calculations revealed that the reaction proceeds via a CH activation/hydrocobaltation pathway

Ynamides were used as precursors for the in situ generation of highly reactive ketenimines that could be trapped with imines in a [2+2] cycloaddition. This imino‐Staudinger synthesis led to a variety of imino‐analogs of β‐lactams, namely azetidinimines (20 examples), that could be further functionalized through a broad range of transformations.

Go cyclic! The use of [Co(H)(PMe3)4] as a cobalt catalyst allows the previously unattainable catalytic version of the cobalt-mediated cycloaddition of enediynes without the requirement of thermal or light activation (see scheme). The importance of a chelating group on the substrate that can selectively direct the reaction pathway toward the classical polycyclic 1,3-cyclohexadienes or a new family of bicyclic trienes is also demonstrated.

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The increasingly worrisome situation of antimicrobial resistances has pushed synthetic chemists to design original molecules that can fight these resistances. To do so, inhibiting β-lactamases, one of the main modes of resistance to β-lactam antibiotics, is one of the most sought-after strategies, as recently evidenced by the development and approval of avibactam, relabactam and vaborbactam. Yet molecules able to inhibit simultaneously β-lactamases belonging to different molecular classes remain scarce and currently there is no metallo-β-lactamase inhibitor approved for clinical use. Having recently developed a synthetic methodology to access imino-analogues of β-lactams (Chem. – Eur. J. 2017, 23, 12991,see ref) we decided to evaluate them as potential β-lactamase inhibitors and specifically against carbapenemases, which can hydrolyze and inactivate penicillins, cephalosporins and carbapenems. Herein we eport our findings that show that our newly developed family of molecules are indeed excellent β-lactamase inhibitors and that our lead compound can inhibit NDM-1 (0.1 µM), KPC-2 (0.4 µM), and OXA-48 (0.6 µM) even though these three enzymes belong to three different molecular classes of carbapenemases. This lead compound also inhibits the ESBL CTX-M-15 and the cephalosporinase CMY-2, it is metabolically stable, and can repotentiate imipenem against a resistant strain of Escherichia coli expressing NDM-1.<br><br><br>

The increasingly worrisome situation of antimicrobial resistances has pushed synthetic chemists to design original molecules that can fight these resistances. To do so, inhibiting β-lactamases, one of the main modes of resistance to β-lactam antibiotics, is one of the most sought-after strategies, as recently evidenced by the development and approval of avibactam, relabactam and vaborbactam. Yet molecules able to inhibit simultaneously β-lactamases belonging to different molecular classes remain scarce and currently there is no metallo-β-lactamase inhibitor approved for clinical use. Having recently developed a synthetic methodology to access imino-analogues of β-lactams (Chem. – Eur. J. 2017, 23, 12991,see ref) we decided to evaluate them as potential β-lactamase inhibitors and specifically against carbapenemases, which can hydrolyze and inactivate penicillins, cephalosporins and carbapenems. Herein we eport our findings that show that our newly developed family of molecules are indeed excellent β-lactamase inhibitors and that our lead compound can inhibit NDM-1 (0.1 µM), KPC-2 (0.4 µM), and OXA-48 (0.6 µM) even though these three enzymes belong to three different molecular classes of carbapenemases. This lead compound also inhibits the ESBL CTX-M-15 and the cephalosporinase CMY-2, it is metabolically stable, and can repotentiate imipenem against a resistant strain of Escherichia coli expressing NDM-1.<br><br><br>