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A convergent synthesis of the dodecasaccharide scaffold of axinelloside A was achieved through Au(I)-catalyzed [6+6] glycosylation. The initially devised [3+1+2] assembly of the nonreducing hexasaccharide fragment was low-yielding, whereas a convergent [3+3] glycosylation under Au(I) catalysis was proven feasible, allowing for a semi-gram scale preparation of the wanted hexasaccharide. The requisite 1,2-cis glycosidic bonds were forged in a highly stereoselective fashion by virtue of remote acetyl group participation, and judicious manipulation of protecting groups. The synthetic dodecasaccharide has been properly protected for the downstream elaboration toward its natural form., (© 2024 Wiley‐VCH GmbH.)

Chemical synthesis of an orthogonally protected hexasaccharide relevant to the reducing-end half of axinelloside A, a highly sulfated marine lipopolysaccharide, is disclosed. The synthesis features preparation of the scyllo-inositol unit via a Ferrier-type-II rearrangement, construction of the 1,2-cis-glycosidic bonds via remote participation, and concise [2+2+2] assembly via Au(I)-catalyzed glycosylation., (© 2024 Wiley‐VCH GmbH.)

A convergent synthesis of the dodecasaccharide scaffold of axinelloside A was achieved through Au(I)‐catalyzed [6+6] glycosylation. The initially devised [3+1+2] assembly of the nonreducing hexasaccharide fragment was low‐yielding, whereas a convergent [3+3] glycosylation under Au(I) catalysis was proven feasible, allowing for a semi‐gram scale preparation of the wanted hexasaccharide. The requisite 1,2‐cis glycosidic bonds were forged in a highly stereoselective fashion by virtue of remote acetyl group participation, and judicious manipulation of protecting groups. The synthetic dodecasaccharide has been properly protected for the downstream elaboration toward its natural form. [ABSTRACT FROM AUTHOR]

Chemical synthesis of an orthogonally protected hexasaccharide relevant to the reducing‐end half of axinelloside A, a highly sulfated marine lipopolysaccharide, is disclosed. The synthesis features preparation of the scyllo‐inositol unit via a Ferrier‐type‐II rearrangement, construction of the 1,2‐cis‐glycosidic bonds via remote participation, and concise [2+2+2] assembly via Au(I)‐catalyzed glycosylation. [ABSTRACT FROM AUTHOR]