Convergent syntheses of C(1→3)-linked disaccharides starting from isolevoglucosenone

Syntheses of β‐C(1→3)‐Glucopyranosides of 2‐ and 4‐Deoxy‐D‐hexoses

“…± The OshimaÀNozaki coupling of enones and aldehydes with Me 2 AlSPh allowed generation of C(1 3 3)-linked disaccharides in a few synthetic steps with high stereoselectivity [7]. Unfortunately, the method is not general yet, and the yield strongly depends on the nature of the aldehyde.…”

“…A new route involving a 1,4-addition of thiophenol to enone 6 was thus developed. In a precedent report [7], we had applied the Oshima-Nozaki condensation [16] to isolevoglucosenone (4) and d-glucopyranose-derived carbaldehyde 5 to generate enone 6 in 80% yield. In the meantime, we have attempted to hydrogenate its alkene moiety but did not find conditions for stereoselective reactions.…”

“…They are potential inhibitors of glycosidases and glycosyltransferases [6]. In this report, we apply our convergent synthetic method for the construction of C(1 3 3)-linked disaccharides [7] to the preparation of yet unknown b-C-glucopyranosides in which a hydroxymethano linker connects b-d-glucopyranose to C(3) of 2-deoxy-d-arabinohexose (see 1), 2-deoxy-d-lyxo-hexose (see 2), and 4-deoxy-d-arabino-hexose (see 3).…”

Synthesis of a (2R,6R)-2-(Hydroxymethyl)-6-propa-1,2-dienyl-2H-pyran-3(6H)-one Derivative, a New Enone for the Convergent Construction of C-Glycosides of C-Disaccharides

“…[4][5][6][7][8] For instance, the conjugate addition of a nucleophile Nu -M + to enones 1 and 2 occurs on their less sterically hindered face 9 leading to enolate intermediates 3 and 4, respectively. These species can add to sugar-derived carbaldehydes of type 5 to generate aldols 6 10 and 7, 5,8 respectively, that are precursors of C(1AE3)-disaccharides (Scheme 1).…”

“…Because of their bicyclic structure levoglucosenone (1) 1 and isolevoglucosenone (2) 2 are attractive templates for the convergent and stereoselective construction of disaccharide mimetics, 3 including C-disaccharides. [4][5][6][7][8] For instance, the conjugate addition of a nucleophile Nu -M + to enones 1 and 2 occurs on their less sterically hindered face 9 leading to enolate intermediates 3 and 4, respectively. These species can add to sugar-derived carbaldehydes of type 5 to generate aldols 6 10 and 7, 5,8 respectively, that are precursors of C(1AE3)-disaccharides (Scheme 1).…”