Aldonolactone sugars synthesis

Aldonolactones are useful starting materials for the synthesis of modified sugars. They have also been used as chiral templates in synthesis of natural products. Some of them are inexpensive, commercially available products or they may be obtained readily from the respective monosaccharides. The purpose of this chapter is to survey the main reactions of aldonolactones. Previous reviews on the subject include articles on gulono-1,4-lactones (1) and D-ribonolactone (2). Methods of synthesis, conformational analysis, and biological properties are not discussed in this chapter. 

Carbene-mediated methylenation of aldonolactones provides a direct route to 1-methylene sugars, which may be used as intermediates for the preparation of furanoid or pyranoid C-glycosyl compounds, or chiral precursors for the synthesis of natural products. 

The cyanohydrin synthesis of higher sugars, which involves intermediate aldonolactones, allows the introduction of a 14C label in the sugar chain. Thus, for example, L-[5-l4C]arabinose was synthesized (12) from D-xylose, which was first converted, by addition of K14CN and hydrolysis, into D-[ 1-... 

Although the use of abundant sugars as starting materials for chiral synthesis has received considerable attention, the ready availability of many aldonolactones is less well recognized by mainstream synthetic organic chemists. The chapter here contributed by de Lederkremer and Varela (Buenos Aires) provides a comprehensive overview of the practical potential of these cyclic esters and complements the more specialized contribution on gulonolactones by Crawford in Volume 38. 

The aim of this article is to focus on the diversity of aldonolactones as chiral synthons. The chemistry of aldonolactones was an almost unexplored area when, in 1979, we started our investigations on the reaction of aldonolactones with hydrogen bromide in acetic acid thereby obtaining bromodeoxyaldonolac-tones [1,2]. These compounds have over the years proven to be very versatile compounds for stereoselective synthesis, both in the carbohydrate field, giving access to otherwise less readily obtainable sugars, and as chiral, optically pure synthons in a broader sense within organic chemistry. 

Some references to acetals of aldonolactones are mentioned in Chapter 6, and a paper on the regioselective acylation of aldono-1,4-lactones is discussed in Chapter 7. See Qiapter 8 fsugar lactones with amino-substituents. The synthesis of S-thio-D-glucohydroximo-l,S-lactone is discussed in (Hiapter 11. 

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