Repurposing a supramolecular iridium catalyst secondary Zn⋯O[double bond, length as m-dash]C weak interactions between the ligand and substrate leads to -selective C(sp)-H borylation of benzamides with unusual kinetics.

The iridium-catalyzed C-H borylation of benzamides typically leads to and selectivities using state-of-the-art iridium-based ,-chelating bipyridine ligands. However, reaching selectivity patterns requires extensive trial-and-error screening molecular design at the ligand first coordination sphere. Herein, we demonstrate that triazolylpyridines are excellent ligands for the selective iridium-catalyzed C-H borylation of tertiary benzamides and, importantly, we demonstrate the almost negligible effect of the first coordination sphere in the selectivity, which is so far unprecedented in iridium C-H bond borylations.

Sustainable Wacker-Type Oxidations.

The Wacker reaction is the oxidation of olefins to ketones and typically requires expensive and scarce palladium catalysts in the presence of an additional copper co-catalyst under harsh conditions (acidic media, high pressure of air/dioxygen, elevated temperatures). Such a transformation is relevant for industry, as shown by the synthesis of acetaldehyde from ethylene as well as for fine-chemicals, because of the versatility of a carbonyl group placed at specific positions. In this regard, many contributions have focused on controlling the chemo- and regioselectivity of the olefin oxidation by means of well-defined palladium catalysts under different sets of reaction conditions.

Unravelling Enzymatic Features in a Supramolecular Iridium Catalyst by Computational Calculations.

Non-biological catalysts following the governing principles of enzymes are attractive systems to disclose unprecedented reactivities. Most of those existing catalysts feature an adaptable molecular recognition site for substrate binding that are prone to undergo conformational selection pathways. Herein, we present a non-biological catalyst that is able to bind substrates via the induced fit model according to in-depth computational calculations.

Enzyme-like Supramolecular Iridium Catalysis Enabling C-H Bond Borylation of Pyridines with meta-Selectivity.

The use of secondary interactions between substrates and catalysts is a promising strategy to discover selective transition metal catalysts for atom-economy C-H bond functionalization. The most powerful catalysts are found via trial-and-error screening due to the low association constants between the substrate and the catalyst in which small stereo-electronic modifications within them can lead to very different reactivities. To circumvent these limitations and to increase the level of reactivity prediction in these important reactions, we report herein a supramolecular catalyst harnessing Zn⋅⋅⋅N interactions that binds to pyridine-like substrates as tight as it can be found in some enzymes.

Beyond hydrogen bonding: recent trends of outer sphere interactions in transition metal catalysis.

Homogeneous catalytic reactions are typically controlled by the stereoelectronic nature of the ligand(s) that bind to the metal(s). The advantages of the so-called first coordination sphere effects have been used for the efficient synthesis of fine chemicals relevant for industrial and academic laboratories since more than half a century. Such level of catalyst control has significantly upgraded in the last few decades by mastering additional interactions beyond the first coordination sphere.