Stereoselective total synthesis of methyl α-d- and α-l-glucopyranosides

https://zenodo.org/record/32921/files/SINOXYGEN-2014-004.pdf

Furans and singlet oxygen – why there is more to come from this powerful partnership

Publisher Summary This chapter describes the syntheses of sugar-type compounds containing four or more carbon atoms, an aldehyde or a ketone group, and a minimum of two hydroxyl groups (or their equivalents, such as amino or thiol groups) with at least one of them being bound to a center of chirality. Among the variety of noncarbohydrate precursors, acetylenes and alkenes have found wide application as substrates for the synthesis of monosaccharides. The parent compounds of all pyranoses—the 2H - and 4H -pyrans—and their derivatives are impractical as substrates for the synthesis of sugars. The formation of furan derivatives in acid-catalyzed dehydrations of carbohydrate substrates is a well known reaction. 1,2-Ethenediyl carbonate (1,3-dioxol-2-one; vinylene carbonate) is a readily available, versatile synthon having pronounced dienophilic properties. For the synthesis of optically active sugars, a number of natural compounds have been successfully employed. The syntheses of sugars described in this chapter demonstrate the general utility of starting materials employed as the precursors of various sugars of desired structure.

The Synthesis of Sugars from Non-Carbohydrate Substrates

A new synthesis of 3-oxocyclopentenes

The increasing interest in Achmatowicz rearrangement in organic synthesis calls for a more environmentally friendly protocol since the most popular oxidants m-CPBA and NBS produced stoichiometric organic side product (m-chlorobenzoic acid or succinimide). Mechanism-guided analysis enables us to develop a new catalytic method (Oxone/KBr) for AchR in excellent yield with K2SO4 as the only side product, which greatly facilitates the purification. This protocol was integrated with other transformations, leading to a rapid access to the highly functionalized dihydropyranones.

Geroges Medawar

Papers

Oxidation of furans. 2. Synthesis and biological properties of 6-hydroxy-2H-pyran-3(6H)-ones and derivatives