Fischer nitromethane cyclization

Scheme 4. Richardson s application of the Fischer nitromethane cyclization to the sugar dialdehyde derived from the periodate cleavage of levoglucosan (1960).

Glycosides of 3-deoxy-3-nitroaldoses are readily available by the cyclization of sugar dialdehydes with nitromethane. Introduced in 1958 by Baer and Fischer,48 the method has been widely employed, and some aspects have been reviewed.49,50 The term sugar dialdehydes refers to products of glycol cleavage of glycosides.51 The formation, structure, conformation, and reaction of such dialdehydes have been discussed in detail in previous Chapters of these Volumes.52-54 The compounds exist in aqueous and alcoholic solutions as solvated, cyclic forms that are internal hemialdals or hemiacetals.54 However, under the conditions of the nitromethane cyclization, mobile equilibria are rapidly shifted from such cyclic products toward carbonyl species, and it is, therefore, permissible and customary in... 

The reaction sequence of Grosheintz and Fischer,98,102 namely, 87 — 88 + 89 — 90 + 91 — 100 + 101 +102, constitutes a stepwise, nitromethane cyclization of xylo-trihydroxyglutaric dialdehyde (99) (xy(o-pentodialdose), a partially protected derivative of which is 87. 

The dialdehyde also underwent a Fischer cyclization with nitromethane and base to produce a mixture of four diasteriomeric nitropyranosides. The principal product was isolated by chromatography, hydrogenated usiag Raney nickel and then A/-acetylated to give... 

A. C. Richardson and H. O. L. Fischer, Cyclizations of dialdehydes with nitromethane, Part V. Preparation of some 3-amino-l,6-anhydro-3-deoxy-P-D-hexoses and the elucidation of their structures, Proc. Chem. Soc. (1960) 341-342. 

Grosheintz and Fischer synthesized the 6-deoxy-6-nitro derivatives of D-glucose and L-idose by treating l,2-0-isopropylidene-a-D-a i/lo-pento-dialdo-l,4-furanose with nitromethane, and employed these sugars for cyclization to cyclitol derivatives. These reactions and their importance in cyclitol chemistry have already been reviewed in this Series. - ... 

An interesting path to the 3-amino-3-deoxyaldoses was found by Fischer and Baer . Periodate cleavage of methylpentop5Tanosides or methyl-pentofuranosides, or of methylhexopyranosides, produces dialdehydes in which the acetal linkage is still maintained. Addition of nitromethane leads to renewed cyclization. After reduction of the nitro group, 3-amino-3-deoxy-aldoses are obtained. Taking methyl-/S-D-ribofuranoside as an example, the formulas show the path of the reaction ... 

---