An efficient and reliable electrochemical generator of hypervalent iodine reagents has been developed. In the anodic oxidation of iodoarenes to hypervalent iodine reagents under flowconditions,the use of electricity replaces hazardous and costly chemical oxidants.U nstable hypervalent iodine reagents can be prepared easily and coupled with different substrates to achieve oxidative transformations in high yields. The unstable,e lectrochemically generated reagents can also easily be transformed into classic bench-stable hypervalent iodine reagents through ligand exchange.T he combination of electrochemical and flow-chemistry advantages largely improves the ecological footprint of the overall process compared to conventional approaches.
A simple synthesis of a library of novel C−N axially chiral iodoarenes is achieved in a three‐step synthesis from commercially available aniline derivatives. C−N axial chiral iodine reagents are rarely investigated in the hypervalent iodine arena. The potential of the novel chiral iodoarenes as organocatalysts for stereoselective oxidative transformations is assessed using the well explored, but challenging stereoselective α‐oxytosylation of ketones. All investigated reagents catalyse the stereoselective oxidation of propiophenone to the corresponding chiral α‐oxytosylated products with good stereochemical control. Using the optimised reaction conditions a wide range of products was obtained in generally good to excellent yields and with good enantioselectivities.
Chiral hypervalent iodine reagents are active players in modern stereoselective organic synthesis. Structurally diverse chiral hypervalent iodine reagents have been synthesised and extensively studied, but hypervalent iodine reagents containing chiral sulfur stereogenic centre are scarce and their synthesis is challenging. A small library of iodoarenes containing chiral sulfinamide and chiral sulfoximine moieties has been synthesised using commercially available reagents. The oxidation of the chiral iodoarene precursors to iodine(III) reagents was cumbersome due to facile overoxidation of the sulfoxide moiety and hence loss of chirality under various oxidation conditions. Oxidation of chiral sulfonimidoyl derivatives to the corresponding hypervalent iodine reagents was successful and led to novel sulfur-based chiral iodine(III) reagents.
Es wurdee in effizienter und zuverlässiger elektrochemischer Generator fürh ypervalente Iodreagenzien entwickelt. Bei der anodischen Oxidation von Iodaromaten zu hypervalenten Iodreagenzien unter Flussbedingungen ersetzt der Einsatz von Elektrizitätg efährliche und teure chemische Oxidationsmittel. Instabile hypervalente Iodreagenzien kçnnen leichthergestellt und mit verschiedenen Substraten zur Reaktion gebrachtwerden, um oxidative Funktionalisierungen mit hohen Ausbeuten zu erreichen. Die instabilen elektrochemische rzeugten Reagenzien kçnnen auchl eichtd urch Ligandenaustauschi nk lassische, stabile hypervalente Iodreagenzien umgewandelt werden. Die Kombination aus elektrochemischen und Flow-chemischen Vorteilen verbessert die çko-logischeBilanz des Prozesses im Vergleichzuherkçmmlichen Ansätzen erheblich.
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