Syntheses with partially benzylated sugars. VII. The anomeric vinyl D-glucopyranosides

Investigations on Leaving Group Based Intra- versus Intermolecular Glycoside Bond Formation

“…[13,17] To this end, two different glycosyl donor and acceptor moieties, each of approximately similar reactivity, have to be ligated through the leaving group. Tetra-O-benzylglucose 17 [27] and tetra-O-(3-methylbenzyl)glucose 18 [13,17] should fulfil this donor requirement (Scheme 5). Similar acceptor properties were exScheme 4.…”

Synthesis and biological activity of [Leu5]enkephalin derivatives containing d‐glucose

“…I ,2,3,4-Tetra-O-acetyl-6-O-([led]-enkephaly1)-P-o-glucopyranose (8) Compound 7 (84mg, 0.072mmol) was hydrogenated for 1 h in a mixture (12mL) of ethanol-acetic acid-water (4: 1 : 1) in the presence of 10% palladium-on-charcoal (50mg). After removal of the catalyst and solvent, the residue was applied to Sephadex G 15 column (70 x 1.2cm) and eluted with 1-0- Benzyl-6-O-(N-tert .- (9) PCPOH (891mg, 3.2mmol) and DCC (659 mg, 3.2 mmol) were added to an ice-cold solution of Boc-Phe-Leu-OH (1209 mg, 3.2 mmol) in 1 ,2-dichloroethane (20 mL). The reaction mixture was stirred for 2 h at room temperature, filtered and added to a solution of benzyl 8-D-glucopyranoside (I 3)(864 mg, 3.2 mmol) and imidazole (285 mg, 4.2 mmol) in DMF (5mL).…”

Synthesis of vinyl glycosides and carbohydrate vinyl ethers from mixed acetals: a hetero-Diels–Alder approach to deoxygenated disaccharides

“…Vinyl glycosides are most often synthesized by transvinylation with mercuric acetate 10 or from glycosyl halides by nucleophilic displacement with bis(acylmethyl)mercury reagents. 11 Elimination reactions of 2-(phenylselenyl)ethyl glycosides 12 and 2-(trimethylammonium)ethyl glycosides, 10 and photolysis of 4-oxopentyl glycosides by Norrish type II reactions also give vinyl glycosides. 13 Palladium-catalyzed vinylation of protected monosaccharides has recently been reported, 14 and Tebbe methylenation has been used to prepared both vinyl glycosides and vinylated sugar derivatives involving a Tetrahedron: Asymmetry nonanomeric hydroxyl group.…”