Synthesis from aldonolactones

Synthesis from aldonolactones The synthesis of p-homonojirimycin (2) from tetra-(9-benzyl-D-glucono-1,5-lactone (56) (Scheme 8) was achieved by treatment of the latter with (methoxymethoxy)methyl lithium to give the a-D-gluco-heptulose derivative 57, which underwent reduction with LiAlITj to produce a mixture of heptitols 58 (1 1 ratio). Oxidation of 58 using Swern oxidation (DMSO-TFAA) gave the heptodiulose 59. Compound 59 was immediately submitted to reductive amination using ammonium formate in the presence of sodium cyanoborohydride to produce 60 in 50% yield from 58. Removal... 

Synthesis from aldonolactone Syntheses of casuarines 249, 253, 261 and 262 from lactone 245 have been reported (Schemes 24 and 25). The triflate in 245 was displaced with azide ion to give the inverted azide, which on reduction with lithium borohydride... 

Synthesis of Nucleosides, Amino Acids, and Other N-Containing Products from Aldonolactones... 

Borchardt and coworkers (265) have employed the chiral cyclopenten-ones derived from aldonolactones for the synthesis of the analogue 302a of neplanocin A. Neplanocin A (302b) and aristeromycin (303), carbocyclic analogs of adenosine having antiviral and antitumor activities, have also been synthesized (277,278). 

Selected examples of the synthesis of natural product starting from aldonolactones are presented in this section. 

Johansen, S.K. et al. Synthesis of Carbasugars from Aldonolactones Ritter-Type Epoxide Opening in the Synthesis of Polyhydroxylated Aminocyclopentanes. 2.1 2.4 1999(132]... 

C. Pedersen and L. Schubert, Synthesis of the four stereoisomers of 4,5-dihydroxy-JV,JV,JV-trim-ethylhexanaminium iodide (muscaridin) from aldonolactones, Acta Chem. ScaruL, 47 (1993) 885-888. 

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. 

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-... 

The regio- and stereo-selective functionalization of aldonolactones yields optically active lactones, which are important precursors in natural product synthesis. Concepts such as chiral templates and chirons, derived from carbohydrates, have been ingeniously and widely applied in synthesis (233). Among the commercially available aldonolactones, D-ribono-1,4-lactone is... 

Methyl oxetane-2-carboxylate derivatives (e.g., 284), obtained by ring contraction of aldonolactones, have been employed for the synthesis (279) of the nucleoside / -noroxetanocin [9-(/ -D-eryt/iro-oxetanosyl)adenine, 304] and its a-anomer via an a-chloride obtained by a modified Hunsdiecker reaction. Displacement of chloride by adenine and debenzylation gave 304. The threo isomer of304, /J-epinoroxetanocin (305), was likewise synthesized from D-lyxono-1,4-lactone. The oxetane nucleosides display potent antiviral activity against the human immunodeficiency virus (HIV). 

As shown in chapter, Synthetic polymers from readily available monosaccharides by J, A, Galbis and M,G, Garcia-Martin, aldonolactones are useful monomeric materials for the synthesis of biodegradable polymers and bio-compatible polymers for medicinal applications. 

Our work has mostly been focussed on the potential of selective transformation of aldonolactones, as will be described in this article, rather than on the synthesis of defined target molecules. Thus, the purpose of this paper is also to inspire researchers from the non-carbohydrate field to recognize these chiral synthons for further use in the synthesis of e.g.complex natural products. 

In planning the synthesis of biologically active compounds, strategies using aldonolactones or other compounds from the chiral pool should therefore continue to be considered, since they can provide attractive routes in comparison with alternative methods by asymmetric synthesis. 

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