Unsaturated Sugars

Ferrier, R. J.

doi:10.1016/s0096-5332(08)60297-0

Cited by 56 publications

(3 citation statements)

References 229 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Use of this base for the 1,2-elimination of hydrogen halides from glycosyl halides to give 2-substituted glycals originates from the work of Maurer and Mahn (9) and has provided a general method for the preparation of per-acetylated 2-hydroxyglycals (10,11). Many of the latter compounds are readily chlorinated to fairly stable, acetylated 2-chloro-2-hydroxy-D-glycopyranosyl chlorides (9,10).…”

mentioning

confidence: 99%

Studies with halogeno sugars. II. A stable free glycosyl chloride

Bradley¹,

Buncel²

1968

Can. J. Chem.

View full text Add to dashboard Cite

Dehydrochlorination of 3,4,6-tri-O-acetyl-2-chloro-2-deoxy-~-~-glucopyranosyl chloride with diethyla~nine yielded 3,4,6-tri-0-acetyl-2-chloro-D-glucal. The latter was further chlorinated to 3,4,6-tri-0-acetyl-2-deoxy-2,2-dichloro-~-~-urubino-hexopyranosy chloride, which on deacetylation provided the first example of a stable, free glycopyranosyl chloride.A 3,4,6-tri-0-acetyl-2-chloro-2-deoxymannopyranosyl chloride, also isolated in this work, was characterized by properties which correspond closely to the recently reassigned anomer.Canadian Journal of Chemistry, 46, 3001 (1968) Although moilohalogen substitution on asymmetric carbon atoms of cyclic sugars has been achieved in ilumerous instances (1) and with each of the four halogens, cyclic sugars with gemdihalogen substitution on ring carbons are comparatively rare. The earliest examples appear to be acetylated 2-deoxy-2,2-dichloro-D-erythropentopyranose and its glycosyl chloride, synthesized by Vargha and Kuszmann (2). More recently Brown and Jones (3) have reported a 3-deoxy-3,3-di-iodo derivative of D-ribo-hexo-1 furanore. Our present work concerns the iilvestigation of synthetic routes to 2,2-dichloro substitution of hexopyranose structures. Electronegative substitution at this position is of particular interest to us in kinetic studies of the 1 acid hydrolysis of glycopyranosides (4). IA long-established route to 2-chlorodeoxy substitution of hexopyranoses has been via chlorination of the 1,2-glycals to 2-chlorodeoxy-D-glycosyl chlorides. In the earliest investigation of this reaction Fischer, Bergmann, and Schotte (5) passed chlorine into a cold solution of tri-0-acetyl-D-glucal (1) in carbon tetrachloride and obtained a product described as 'triacetylglucal dichloride'. Recent investigations of this substance using modern analytical techniques show that it is a mixture of gluco (2) and n7anno (3) epimers. Lemieux and Fraser-Reid (6), using nuclear magnetic resonance spectroscopy 1 (n.m.r.), reported the a-D-gluco dichloride as the main product in greater than 80% yield, but did not detect the manno dichloride. Subsequently I Lefar and Weill (7) subjected a crystalline sample I of the dichloro-triacetyl-glycal to thin-layer chromatography (t.1.c.) and showed that it was a mixture of two major components which they identified by n.m.r. as the a-D-gluco and a-Dmanno dichlorides in a ratio of roughly 4 : 1. The results of the present work are qualitatively similar to those of Lefar and Weill, as far as the ratio of the two compoilents is concerned, but the minor component exhibits significantly different physical properties and n.m.r. spectrum (vide infra). Very recently, since the completion of our work, Igarashi, Honma, and Imagawa have reported (8) mainly by a four-centered transition state or a concerted mechanism, which is in contrast to the two-stage oxocarbonium mechanism proposed by . In 1963 Vargha and Kuszmann (2) reported a series of reactions leading from 3,4-di-0-acetyl-D-arabinal to an acetylated 2,2-dichloro-2-deoxy-D-pentose. Chlorinatio...

show abstract

mentioning

confidence: 99%

Studies with halogeno sugars. II. A stable free glycosyl chloride

Bradley¹,

Buncel²

1968

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…Treatment with nucleophiles of glycals [11] carrying allylic acetoxy group in the presence of acids is known to result in the formation of 2,3-unsaturated glycosides via Ferrier rearrangement. [12,13] In general, the oxonium ion intermediate is attacked by an O-, N-, or S-nucleophile predominantly at C-1 and results in the formation of Ferrier products. The regiocontrolled glycosylation of Ferrier rearrangement (C-1 vs C-3 reaction) has been explained in terms of the hard-soft acidbase principle.…”

Section: Introductionmentioning

confidence: 99%

Lewis Acid Catalysed Regioselective Access of Novel C‐2 Homo‐Pyranose Nucleosides From 2‐Acetoxy Methyl Glycals

2023

View full text Add to dashboard Cite

show abstract

“…The conversion of 1 to 2 was chosen for preliminary investigation since 1 is readily available (18) and 2 has been well characterized (7,19). A cursory study of this transformation has been reported (4) but in view of our desire to develop a method capable of relatively large scale operation5 we pursued the investigation further.…”

mentioning

confidence: 99%

Some aspects of the formation of hex-2-enopyranosides from methyl 2,3-di-O-methanesulfonyl-α-D-glucopyranosides

Fraser‐Reid¹,

Boctor²

1969

Can. J. Chem.

View full text Add to dashboard Cite

The elimination of vicinal sulfonyloxy groups fro111 methyl 2,3-di-O-n1ethanesulfonyl-a-~-gIucopyranosides with the formation of hex-2-enopyranosides using potassium iodide, and zinc in refluxing dry dimethyl formamide has been investigated. The specific use of a zinc-copper couple has been found to be highly advantageous to the yield and reproducibility of the reaction, and the elimination proceeds successfully whether acid or base labile groups are present at carbon-4 or -6. Both the 4,6-di-0-benzoyl (3b) and the 6-0-benzoyl (3d) precursors give methyl 6-O-benzoyl-r-~-ery1ht~-11ex-2-enopyrano~ide ( 4 4 as the major product, the latter also being obtainable by selective benzoylation of methyl a-D-eqzrktohex-2-enopyranoside (4c). The reaction of the dibenzoate therefore occurs with some deacylation at carbon-4, but it is noteworthy that this is not accompanied by any epimerization. A sinlilar pattern of reaction apparently occurs with the 4,6-di-0-acetyl derivative (3a). The confornlations of the starting di-0-methanesulfonyl esters are discussed and suggestions for the n.nl.r. assignments of the groups are made.

show abstract

Unsaturated Sugars

Cited by 56 publications

References 229 publications

Studies with halogeno sugars. II. A stable free glycosyl chloride

Studies with halogeno sugars. II. A stable free glycosyl chloride

Lewis Acid Catalysed Regioselective Access of Novel C‐2 Homo‐Pyranose Nucleosides From 2‐Acetoxy Methyl Glycals

Some aspects of the formation of hex-2-enopyranosides from methyl 2,3-di-O-methanesulfonyl-α-D-glucopyranosides

Contact Info

Product

Resources

About