Publication

Total Asymmetric Syntheses of 1,5-Dideoxy-1,5-Iminooctitols and 1,2,6,7,8-Pentahydroxyindolizidines

Pierre Vogel
1994
Journal Articles

Abstract

(1R,4R,5S,6S,7S)-4-exo-[(1'S,2'R)-1'-Hydroxy-2',3'-(isopropylidenedioxy) propyl]-6-exo,7-exo-(isopropylidenedioxy)-2,8-dioxabicyclo[3.2.1]octan-3 -one ((+)-5) and its diastereomer (1S,4S,5R,6R,7R)-(1'R,2'R)-(-)-30 derived from (R)-2,3-O-isopropylideneglyceraldehyde and (+/-)-5-exo,6-exo-(isopropylidenedioxy)-7-oxabicyclo[2.2.1]hept-2-one were alcoholyzed with benzyl alcohol in CCl4 (CsF as base) into the corresponding 5-C-(benzyloxycarbonly)-5-deoxyoctofuranoses (+)-9 and (-)-31 which were converted via Curtius rearrangements into (-)-1,5-dideoxy-1,5-imino-D-erythro-D-talo-octitol ((-)-20) and its D-threo-L-talo isomer (+)-36, respectively, Alcoholyses of (+)-5 and (-)-30 with benzyl alcohol in DMSO in the presence of CsF or K2CO3 led to the epimerized benzyl esters (-)-10 and (-)-38, respectively, which were converted into (-)-1,5-didoexy-1,5-imino-D-erythro-6-allo-octitol ((-)-27) and its D-threo-D-allo isomer (+)-42. The 1,5-dideoxy-1,5-iminooctitols were converted into the corresponding 1,2,6,7,8-pentahydroxyindolizidines in a single step.

Official source

https://infoscience.epfl.ch/entities/publication/d25ae7e3-2fa4-4532-bb65-f10ed2deabda

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Pierre Vogel
1994
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/d25ae7e3-2fa4-4532-bb65-f10ed2deabda

About this result

Related concepts (4)

Curtius rearrangement

The Curtius rearrangement (or Curtius reaction or Curtius degradation), first defined by Theodor Curtius in 1885, is the thermal decomposition of an acyl azide to an isocyanate with loss of nitrogen gas. The isocyanate then undergoes attack by a variety of nucleophiles such as water, alcohols and amines, to yield a primary amine, carbamate or urea derivative respectively. Several reviews have been published. The acyl azide is usually made from the reaction of acid chlorides or anydrides with sodium azide or trimethylsilyl azide.

Hofmann rearrangement

The Hofmann rearrangement (Hofmann degradation) is the organic reaction of a primary amide to a primary amine with one less carbon atom. The reaction involves oxidation of the nitrogen followed by rearrangement of the carbonyl and nitrogen to give an isocyanate intermediate. The reaction can form a wide range of products, including alkyl and aryl amines. The reaction is named after its discoverer, August Wilhelm von Hofmann, and should not be confused with the Hofmann elimination, another name reaction for which he is eponymous.

Rearrangement reaction

In organic chemistry, a rearrangement reaction is a broad class of organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule. Often a substituent moves from one atom to another atom in the same molecule, hence these reactions are usually intramolecular. In the example below, the substituent R moves from carbon atom 1 to carbon atom 2: Intermolecular rearrangements also take place.