Efficient synthesis of multifunctional furanoid C-glycoamino acid precursors

Synthesis of multiply fluorinated N-acetyl-D-glucosamine and D-galactosamine analogs via the corresponding deoxyfluorinated glucosazide and galactosazide phenyl thioglycosides

“…The ring contraction may involve formation of a transient oxiranium cation as suggested in Scheme 2 [42][43][44][45]. Analogous ring-contraction reactions have been described for substrates possessing a good C2 leaving group [42,[46][47][48][49][50].…”

A Novel Approach to the Synthesis of N-Substituted 1-C-Aminomethyl Glycofuranosides

“…10,11 Treatment of the crude aldehyde obtained in situ by hydrolysis (9:1 TFA-H 2 O, r.t., 1 h) of the dimethyl acetal 6, with diverse primary or secondary amines (1.4 mol equiv) in dry 1,2-dichloroethane, and subsequent reduction of the respective, not isolated, imine using sodium triacetoxyborohydride (1.4 mol equiv), afforded the respective compounds 7a-h in moderate to high yields (Scheme 2, Table 1). 12 Their deprotection with 1 M NaMeO-MeOH gave the corresponding products 8a-h. 13 As shown in Table 1, primary and secondary aliphatic amines (benzylamine, piperidine, benzyloxycarbonyl piperazine, and morpholine, entries 1-4), as well as the aromatic amine 4-hydroxymethyl aniline (entry 6), gave the corresponding reductive amination compounds 7a-e as the sole product.…”

Efficient Two-Step Multifunctionalization of Substituted 2-Hydro­xyglycopyranosides

“…Based on our previous experience, 24 fluorination using Et 3 N•3HF of the epimeric mixture of 9/10 obtained from reaction of α+β diastereoisomers 7/8 with trifluoromethanesulfonic anhydride was carried out. An antiperiplanar disposition between C-OTf and C-O is required to enable the oxygen exocyclic attack to C-2 position.…”