Silver-catalyzed synthesis of β-fluorovinylphosphonates by phosphonofluorination of aromatic alkynes

A silver-catalyzed three-component reaction involving alkynes, Selectfluor®, and diethyl phosphite was employed for the one-pot formation of C(sp2)–F and C(sp2)–P bonds to provide an efficient access to β-fluorovinylphosphonates in a highly regio- and stereoselective manner under mild reaction conditions. This reaction is operationally simple and offers an excellent functional group tolerance as well as a broad substrate scope that includes both terminal and internal alkynes. The reaction proceeded through the oxidative generation of a P-centered radical and subsequent fluorine atom transfer.

Oxidative Generation of Boron-Centered Radicals in Carboranes

<div><div><div><p>We report the first indirect observation and use of boron vertex-centered carboranyl radicals generated by the oxidation of modified carboranyl precursors. These radical intermediates are formed by the direct oxidation of a B−B bond between a boron cluster cage and an exopolyhedral boron-based substituent (e.g., −BF3K, −B(OH)2). The in situ generated radical species are shown to be competent substrates in reactions with oxygen-based radicals, dichalcogenides, and N-heterocycles, yielding the corresponding substituted carboranes containing B−O, B−S, B−Se, B−Te, and B−C bonds. Remarkably, this chemistry tolerates various electronic environments, providing access to facile substitution chemistry at both electron-rich and electron-poor B−H vertices in carboranes.</p></div></div></div>

Oxidative Generation of Boron-Centered Radicals in Carboranes

<div><div><div><p>We report the first indirect observation and use of boron vertex-centered carboranyl radicals generated by the oxidation of modified carboranyl precursors. These radical intermediates are formed by the direct oxidation of a B−B bond between a boron cluster cage and an exopolyhedral boron-based substituent (e.g., −BF3K, −B(OH)2). The in situ generated radical species are shown to be competent substrates in reactions with oxygen-based radicals, dichalcogenides, and N-heterocycles, yielding the corresponding substituted carboranes containing B−O, B−S, B−Se, B−Te, and B−C bonds. Remarkably, this chemistry tolerates various electronic environments, providing access to facile substitution chemistry at both electron-rich and electron-poor B−H vertices in carboranes.</p></div></div></div>

Copper-Catalyzed Amination of Vinyl Azides to α-Ketoamides

An efficient approach for the amination of vinyl azides with N,N-dialkylacylamides has been developed. By using this protocol, structurally important α-ketoamides can be easily synthesized. The key to success is not only the introduction of a Cu(I)/oxygen catalytic system but also the utilization of t-BuOCl and benzoic acid as additives. The reaction is operationally simple, scalable, and displays broad scope and functional group tolerance. A possible mechanism involving copper-catalyzed oxidative generation of peroxide radicals is proposed.

A karbonilstressz szerepe a diabetes szövődményeinek kialakulásában

The relationship between the potentially developing complications of the 451 million people affected by diabetes and hyperglycaemia can be based on the enhanced generation of advanced glycation endproducts and the more intensive oxidative and carbonyl stress. Advanced glycation endproducts generated partly due to carbonyl stress play an important role in the pathogenesis of diabetic complications such as elevated arterial thickness, vascular permeability, enhanced angiogenesis or the more rigid vessels induced nephropathy, neuropathy, retinopathy. Furthermore, the elevated thrombocyte aggregation, the reduced fibrinolysis induced elevated coagulation, and the atherosclerosis or the mitochondrial dysfunction are important as well. The most potent target of both the non-oxidative and oxidative generation of advanced glycation endproducts can be the scavenging of α,β-unsaturated aldehydes. Although, aminoguanidine, the prototype of scavenger molecules, showed protection in different animal models, it failed in the human clinical studies. Finally, the clinical studies were terminated almost 20 years ago. The endogen dipeptide L-carnosine was also expected to mitigate the complications due to carbonyl stress. However, its clinical significance was limited by the serum carnosinases and by the consequent low serum stability and bioavailability. The carnosinase resistance of the molecule can be achieved by the change of the carboxyl group of the molecule to hydroxyl group. At the same time, the biosafety and the carbonyl stress scavenging activity of the molecule could be preserved. Although clinical studies could not be performed in the last six months, on the basis of the in vitro and in vivo results, carnosinole seems to be a promising compound to mitigate and prevent the diabetic complications. Thus it is worth to the attention of the clinicians. Orv Hetil. 2019; 160(40): 1567–1573.