Synthesis and Rearrangement of Epoxy Sugars
(1997)- Abstract
- Ring-Contraction of sugar-derived epoxy alcohols, functionalised in position 1 and 6, by treatment with lithium bromide and N, N, N', N'-tetramethylurea in refluxing toluene gave enantiomerically pure a,b-unsaturated aldehydes of furanosides. O-Glycosidic epoxy alcohols gave only one, easily purified, aldehyde in approximately 30-60% yield depending on the substitution pattern. C-Glycosidic epoxy alcohols gave an isomeric mixture, in ratio 1:4, of two aldehydes which could not be separated. The major isomer confirmed that two aldehydes were formed also from O-glycosides but that one isomer is destroyed during the reaction thereby accounting for the low yield of the isolated isomer. Alkylation with methyl... (More)
- Ring-Contraction of sugar-derived epoxy alcohols, functionalised in position 1 and 6, by treatment with lithium bromide and N, N, N', N'-tetramethylurea in refluxing toluene gave enantiomerically pure a,b-unsaturated aldehydes of furanosides. O-Glycosidic epoxy alcohols gave only one, easily purified, aldehyde in approximately 30-60% yield depending on the substitution pattern. C-Glycosidic epoxy alcohols gave an isomeric mixture, in ratio 1:4, of two aldehydes which could not be separated. The major isomer confirmed that two aldehydes were formed also from O-glycosides but that one isomer is destroyed during the reaction thereby accounting for the low yield of the isolated isomer. Alkylation with methyl 2,3-anhydro-6-deoxy-6-bromo-a-D-allopyranoside of various allyl-sulfides and -sulfones under hexabutyldistannane-induced radical conditions gave the C-6-allylated sugar epoxides in good yields. Acetobromogalactose alkylated the allyl-sulfides and -sulfones under the same conditions to give C-a-galactosides in good yields. Alkylation of methyl 2,3-anhydro-6-deoxy-6-bromo-a-D-allopyranoside by treatment with furfuryl- and decylmercaptan in dimethylformamide, with potassium carbonate as base, gave the corresponding sulfides in position 6 in good yields. Oxidation of sulfur with 4-chloroperbenzoic acid gave the corresponding sulfones. Epoxidation of partly protected 2,2,2-trichloroethyl, and furfuryl glucosides by treatment with triphenylphosphine and diethyl azodicarboxylate in refluxing toluene gave epoxide mixtures, mainly of the corresponding 2,3-anhydro-allopyranoside. C-Glycosidic epoxy alcohols were prepared from C-propyl tetra-O-acetyl-a-D-glucoside by treatment of a mixture of monotosylates with sodium methoxide in methanol. Intramolecular Diels-Alder reaction of an unsaturated aldehyde carrying a suitable linked furfurylsulfide gave one single polycyclic oxanorbornane in good yield. The Diels-Alder reaction was affected by slowly eluting the unsaturated aldehyde on a silica column. Reduction or oxidation of the aldehyde adduct followed by a number of selective transformations gave a series of polycyclic oxanorbornanes. Oxanorbornanes, where the sulfide has been oxidised to a sulfone carries three oxygens geometrically well arranged for coordination of lithium or magnesium ion. One synthetic example of a reaction where the oxanorbornane might act as a crown ether was found. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/29239
- author
- Pontén, Fritiof LU
- supervisor
- opponent
-
- Prof Moberg, Christina, Stockholm
- organization
- publishing date
- 1997
- type
- Thesis
- publication status
- published
- subject
- keywords
- Organisk kemi, Organic chemistry, crown ether, silica, Intramoleculaf Diels-Alder reaction, radical allylation, allyl sulfone, sugar epoxide, allyl sulfide, ring-contraction, C-glycoside, a, IMDAF, b-unsaturated aldehyde
- pages
- 62 pages
- publisher
- Organic Chemistry, Lund University
- defense location
- Centre of Chemistry, Sölvegatan 39, Lund, lecture hall C
- defense date
- 1997-05-07 13:15:00
- external identifiers
-
- other:LUTKDH/(TKOK-1043)/1-62/(1997)
- ISBN
- 91-628-2462-7
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Organic chemistry (S/LTH) (011001240)
- id
- 0f878aa8-0a7f-469b-bb1d-94d52033d701 (old id 29239)
- date added to LUP
- 2016-04-04 11:16:28
- date last changed
- 2018-11-21 21:03:45
@phdthesis{0f878aa8-0a7f-469b-bb1d-94d52033d701,
abstract = {{Ring-Contraction of sugar-derived epoxy alcohols, functionalised in position 1 and 6, by treatment with lithium bromide and N, N, N', N'-tetramethylurea in refluxing toluene gave enantiomerically pure a,b-unsaturated aldehydes of furanosides. O-Glycosidic epoxy alcohols gave only one, easily purified, aldehyde in approximately 30-60% yield depending on the substitution pattern. C-Glycosidic epoxy alcohols gave an isomeric mixture, in ratio 1:4, of two aldehydes which could not be separated. The major isomer confirmed that two aldehydes were formed also from O-glycosides but that one isomer is destroyed during the reaction thereby accounting for the low yield of the isolated isomer. Alkylation with methyl 2,3-anhydro-6-deoxy-6-bromo-a-D-allopyranoside of various allyl-sulfides and -sulfones under hexabutyldistannane-induced radical conditions gave the C-6-allylated sugar epoxides in good yields. Acetobromogalactose alkylated the allyl-sulfides and -sulfones under the same conditions to give C-a-galactosides in good yields. Alkylation of methyl 2,3-anhydro-6-deoxy-6-bromo-a-D-allopyranoside by treatment with furfuryl- and decylmercaptan in dimethylformamide, with potassium carbonate as base, gave the corresponding sulfides in position 6 in good yields. Oxidation of sulfur with 4-chloroperbenzoic acid gave the corresponding sulfones. Epoxidation of partly protected 2,2,2-trichloroethyl, and furfuryl glucosides by treatment with triphenylphosphine and diethyl azodicarboxylate in refluxing toluene gave epoxide mixtures, mainly of the corresponding 2,3-anhydro-allopyranoside. C-Glycosidic epoxy alcohols were prepared from C-propyl tetra-O-acetyl-a-D-glucoside by treatment of a mixture of monotosylates with sodium methoxide in methanol. Intramolecular Diels-Alder reaction of an unsaturated aldehyde carrying a suitable linked furfurylsulfide gave one single polycyclic oxanorbornane in good yield. The Diels-Alder reaction was affected by slowly eluting the unsaturated aldehyde on a silica column. Reduction or oxidation of the aldehyde adduct followed by a number of selective transformations gave a series of polycyclic oxanorbornanes. Oxanorbornanes, where the sulfide has been oxidised to a sulfone carries three oxygens geometrically well arranged for coordination of lithium or magnesium ion. One synthetic example of a reaction where the oxanorbornane might act as a crown ether was found.}},
author = {{Pontén, Fritiof}},
isbn = {{91-628-2462-7}},
keywords = {{Organisk kemi; Organic chemistry; crown ether; silica; Intramoleculaf Diels-Alder reaction; radical allylation; allyl sulfone; sugar epoxide; allyl sulfide; ring-contraction; C-glycoside; a; IMDAF; b-unsaturated aldehyde}},
language = {{eng}},
publisher = {{Organic Chemistry, Lund University}},
school = {{Lund University}},
title = {{Synthesis and Rearrangement of Epoxy Sugars}},
year = {{1997}},
}