Chemistry of Anhydro Sugars

d-Idose-Based Monoaza-15-Crown-5 Lariat Ethers: Synthesis of an Elusive d-Hexose and Application of Derived Macrocycles in Enantioselective Syntheses

“…Compound 4 was then reacted with a 3 M sodium methoxide/methanol solution in dry 1,4-dioxane to facilitate the formation of an oxirane ring at positions 2 and 3 [28]. According to the literature, this reaction proceeds with an intramolecular S N 2 mechanism [29]: The reaction starts with the cleavage of an S-O bond in one of the sulfonic ester groups resulting in an oxyanion, which can then directly attack the neighboring carbon atom. Since there is still another tosylate group attached to this atom, which is a good leaving group, the formation of the oxirane ring is allowed.…”

“…The free hydroxy groups in galactopyranoside 3 were then subj chloride in chloroform/pyridine, resulting in 2,3-ditosylate 4 in an 85 [27]. Compound 4 was then reacted with a 3 M sodium methoxide/m dry 1,4-dioxane to facilitate the formation of an oxirane ring at pos According to the literature, this reaction proceeds with an intramolec [29]: The reaction starts with the cleavage of an S-O bond in one o groups resulting in an oxyanion, which can then directly attack the atom. Since there is still another tosylate group attached to this ato leaving group, the formation of the oxirane ring is allowed.…”

Expedient synthesis of 1,6-anhydro-α-D-galactofuranose, a useful intermediate for glycobiological tools

“…They are valuable intermediates not only in carbohydrate synthesis, but also as starting materials for other natural and non-natural complex products and bioactive compounds. Among the glycosans, the anhydro sugars involving the anomeric center in the ring formation, the 1,6-anhydro sugars are the most common and useful building blocks [1–2]. They can play a role in synthetic methodologies aiming at the obtainment of regioselectively functionalized sugars in a few steps, which could give easy access to convenient glycosyl donors and acceptors [3].…”