Electrochemical Glycosylation via Halogen-Atom-Transfer for -Glycoside Assembly.

Glycosyl donor activation emerged as an enabling technology for anomeric functionalization, but aimed primarily at -glycosylation. In contrast, we herein disclose mechanistically distinct electrochemical glycosyl bromide donor activations via halogen-atom transfer and anomeric -glycosylation. The anomeric radical addition to alkenes led to -alkyl glycoside synthesis under precious metal-free reaction conditions from readily available glycosyl bromides.

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.

Ruthenium(II)-catalyzed oxidative dehydrogenation and hydroarylation of maleimides with phthalazinones - insights into additive-controlled product selectivity.

Herein, we developed ruthenium(II)-catalyzed oxidative dehydrogenation and hydroarylation of maleimides with phthalazinones. The product selectivity is controlled by the additives, and the hydroarylated product was obtained in water, which is an important highlight of this study. Control experiments were conducted to elucidate a plausible mechanism.

Domino meta-C-H Ethyl Glycosylation by Ruthenium(II/III) Catalysis: Modular Assembly of meta-C-Alkyl Glycosides.

Glycosyl anomeric radical addition reactions have been well-explored and proved efficient for the C-alkyl glycosides synthesis, but multicomponent Domino transformations for the rapid and controllable construction of structurally diversified C-alkyl glycosides in a single step are still rare. In contrast, we, herein, report a ruthenium(II)-catalyzed Domino meta-C-H ethyl glycosylation, enabling the construction of challenging meta-C-alkyl glycosides. Our ruthenium(II) catalysis was reflected by the mild reaction condition, exclusive meta-site selectivity and high levels of anomeric selectivity.

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.

Acylation of oxindoles using methyl/phenyl esters via the mixed Claisen condensation - an access to 3-alkylideneoxindoles.

Predominantly, aggressive acid chlorides and stoichiometric coupling reagents are employed in the acylating process for synthesizing carbonyl tethered heterocycles. Herein, we report simple acyl sources, viz. methyl and phenyl esters, which acylate oxindoles via the mixed Claisen condensation.