Visible light activation enables desulfonylative cross-coupling of glycosyl sulfones

Electrochemically Enabled Intramolecular Amino- and Oxysulfonylation of Alkenes with Sodium Sulfinates to Access Sulfonylated Saturated Heterocycles

“…Among established synthetic methodologies toward the synthesis of saturated heterocycles, the straightforward intramolecular difunctionalization of alkenes equipped with nucleophilic heteroatom-containing groups could enable the construction of a heterocyclic framework and the simultaneous incorporation of an additional functional group in a one-pot process with incredible bond-forming efficiency and high atom economy . In terms of the biological features and synthetic applications of functionalized saturated heterocycles, the introduction of sulfonyl groups into parent heterocycle compounds via the alkene difunctionalization strategy has become an important research field of synthesis chemistry due to the unique physical and biological properties of sulfonyl groups as well as their potential synthetic transformations . Since the pioneering works of Buchwald, a broad range of alkenes equipped with pendant oxygen- and nitrogen-based nucleophilic functional groups, such as alcohol, oxime, carboxylic acid, amide, and imidate, have been transformed into sulfone-containing heterocycles under copper-catalyzed or photoinduced conditions (Scheme A).…”

StereoselectiveC‐Aryl Glycosylation by Catalytic Cross‐Coupling of Heteroaryl Glycosyl Sulfones

“…These problems led us to bench‐stable heteroaryl glycosyl sulfones, [31, 32] of which a diverse spectrum of carbohydrate residues can be readily prepared and dispensed on large scale [33] . Under transition‐metal‐free photoinduced conditions, these sulfones were found to undergo desulfonylative coupling with activated π‐bonds and electrophiles to furnish certain classes of glycosides through glycosyl radical addition/elimination pathways [34] (Scheme 2a). Despite these advances, severe limitations in the range of accessible saccharides still exist, since reactions with less‐activated aryl‐substituted reagents leading to C ‐aryl glycosides were unsuccessful [34] …”

“…Despite these advances, severe limitations in the range of accessible saccharides still exist, since reactions with less-activated aryl-substituted reagents leading to C-aryl glycosides were unsuccessful. [34] Therefore, there is an urgent demand to develop transformations that fully leverage heteroaryl glycosyl sulfones as a general class of donors for stereoselective C-aryl glycosylation, exhibiting high functional-group tolerance with respect to the scope of the sugar residue and aryl moiety. To achieve this, we envisioned that an appropriate base metal catalyst can be exploited to activate the aromatic reaction partner, in order to promote efficient desulfonylative CÀ C cross-coupling with the sulfone.…”

Domino‐meta‐C−H‐Ethylglykosylierung durch Ruthenium(II/III)‐Katalyse: Modularer Aufbau von meta‐C‐Alkylglykosiden

“…[4] Die anschließenden anomeren Radikaladditionen vom Giese-Typ an aktivierte Alkenen mit Zinnhydrid mittels Bestrahlung, bildeten die Grundlage für die Synthese von C-Alkylglykosiden, [5] unter den zinnfreie Varianten. Beispielsweise verbesserten die Kombination von BEt 3 /O 2 als Radikalpromotor, [6] Photoredox-Katalyse mit sichtbarem Licht, [7] Aktivierung mit sichtbarem Licht, [8] Samarium(II)-vermittelte radikalische Addition [9] und Titankatalyse, [10] deren Anwendbarkeit (Schema 1a). In den letzten Jahren hat sich die unkomplizierte CÀ H-Glykosylierung [11] als ein zuverlässiges Werkzeug für den effizienten und modularen Aufbau von C-Glykosiden erwiesen.…”