Triple Role of Proton Sponge (DMAN) in the Palladium-Catalyzed Direct Stereoselective Synthesis of C‑Aryl Glycosides from Glycals

The triple role of 1,8-bis­(dimethylamino)­naphthalene (proton sponge) as a reductant, ligand precursor, and organic base in the palladium-catalyzed Heck-type coupling reaction of glycals with aryl iodides affords the rapid and stereoselective synthesis of 2′,3′-unsaturated α-C-aryl glycosides in ex...

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Veröffentlicht in:Organic letters 2024-05, Vol.26 (17), p.3563-3568
Hauptverfasser: Pradhan, Priyanka, Moktan, Sangay, Biswas, Ashish, Das, Animesh, Lenka, Rajesh, Kancharla, Pavan K.
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Sprache:eng
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Zusammenfassung:The triple role of 1,8-bis­(dimethylamino)­naphthalene (proton sponge) as a reductant, ligand precursor, and organic base in the palladium-catalyzed Heck-type coupling reaction of glycals with aryl iodides affords the rapid and stereoselective synthesis of 2′,3′-unsaturated α-C-aryl glycosides in excellent yields. The role of the proton sponge in reducing palladium­(II) to (0) has been studied using cyclic voltammetry, UV–vis, HRMS, and other spectroscopic techniques. This is the first example of a palladium proton sponge complex utilized in coupling reactions. The method is observed to be tolerant of various functional groups, as demonstrated by the huge substrate scope. Moreover, the 2′,3′-unsaturated α-C-aryl glycosides were also converted to 3-keto-β-C-glycosides under sterically hindered pyridinium salt catalysis via a ring-opening and -closing mechanism.
ISSN:1523-7060
1523-7052
DOI:10.1021/acs.orglett.4c00997