Synthesis of peracetylated D-galactopyranosylidene dihalides

J P Praly, J C Brendle, J Klett, F Pequery

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Upon treatment with aluminium trichloride in absolute chloroform, beta -D-galactopyranose penta-O-acetate was converted in high yield into tetra-O-acetyl-beta -D-galactopyranosyl chloride. In the presence of N-bromosuccinimide in boiling carbon tetrachloride, homolytic substitution of the anomeric hydrogen atom in this beta -chloride occurred selectively to afford tetra-O-acetyl-1-bromo-beta -D-galactopyranosyl chloride, in admixture with minor amounts of tetra-O-acetyl-D-galactopyranosylidene chloride. Bromine substitution by fluorine took place with a low stereoselectivity in tetra-O-acetyl-1-bromo-beta -D-galactopyranosyl chloride when treated with 1.25 equiv silver fluoride in acetonitrile, whereas tetra-O-acetyl-beta -galactopyranosylidene fluoride could be prepared in 54% yield with 3.3 equiv AgF. The gem-difluoride could be deacetylated quantitatively. Upon treatment with 1,4-diazabicyclo[2.2.2] octane, peracetylated 1-bromo-beta -D-galactopyranosyl chloride underwent 1,2-elimination of hydrogen bromide to afford 2,3,4,6-tetra-0-acetyl-D-lyxo-hex-1-enopyranosyl chloride in 33 % yield. (C) 2001 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.

Original languageEnglish
Pages (from-to)611-617
Number of pages7
JournalComptes Rendus - Academie des Sciences Paris Serie 2 Chimie Fascicule C
Volume4
Issue number7
DOIs
Publication statusPublished - Jul 2001

Fingerprint

Chlorides
Substitution reactions
Hydrobromic Acid
Bromosuccinimide
Gems
Stereoselectivity
Bromine
Fluorine
Carbon Tetrachloride
Chloroform
Fluorides
Galactose
Boiling liquids
Hydrogen
Acetates
Atoms

Keywords

  • radical bromination of tetra-O-acetyl-beta-D-galactopyranosyl chloride
  • pyranosylgem-dihalides
  • sugars
  • spectroscopy
  • fluoride
  • glycals

Cite this

Praly, J P ; Brendle, J C ; Klett, J ; Pequery, F . / Synthesis of peracetylated D-galactopyranosylidene dihalides. In: Comptes Rendus - Academie des Sciences Paris Serie 2 Chimie Fascicule C. 2001 ; Vol. 4, No. 7. pp. 611-617.
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Synthesis of peracetylated D-galactopyranosylidene dihalides. / Praly, J P ; Brendle, J C ; Klett, J ; Pequery, F .

In: Comptes Rendus - Academie des Sciences Paris Serie 2 Chimie Fascicule C, Vol. 4, No. 7, 07.2001, p. 611-617.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Synthesis of peracetylated D-galactopyranosylidene dihalides

AU - Praly, J P

AU - Brendle, J C

AU - Klett, J

AU - Pequery, F

PY - 2001/7

Y1 - 2001/7

N2 - Upon treatment with aluminium trichloride in absolute chloroform, beta -D-galactopyranose penta-O-acetate was converted in high yield into tetra-O-acetyl-beta -D-galactopyranosyl chloride. In the presence of N-bromosuccinimide in boiling carbon tetrachloride, homolytic substitution of the anomeric hydrogen atom in this beta -chloride occurred selectively to afford tetra-O-acetyl-1-bromo-beta -D-galactopyranosyl chloride, in admixture with minor amounts of tetra-O-acetyl-D-galactopyranosylidene chloride. Bromine substitution by fluorine took place with a low stereoselectivity in tetra-O-acetyl-1-bromo-beta -D-galactopyranosyl chloride when treated with 1.25 equiv silver fluoride in acetonitrile, whereas tetra-O-acetyl-beta -galactopyranosylidene fluoride could be prepared in 54% yield with 3.3 equiv AgF. The gem-difluoride could be deacetylated quantitatively. Upon treatment with 1,4-diazabicyclo[2.2.2] octane, peracetylated 1-bromo-beta -D-galactopyranosyl chloride underwent 1,2-elimination of hydrogen bromide to afford 2,3,4,6-tetra-0-acetyl-D-lyxo-hex-1-enopyranosyl chloride in 33 % yield. (C) 2001 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.

AB - Upon treatment with aluminium trichloride in absolute chloroform, beta -D-galactopyranose penta-O-acetate was converted in high yield into tetra-O-acetyl-beta -D-galactopyranosyl chloride. In the presence of N-bromosuccinimide in boiling carbon tetrachloride, homolytic substitution of the anomeric hydrogen atom in this beta -chloride occurred selectively to afford tetra-O-acetyl-1-bromo-beta -D-galactopyranosyl chloride, in admixture with minor amounts of tetra-O-acetyl-D-galactopyranosylidene chloride. Bromine substitution by fluorine took place with a low stereoselectivity in tetra-O-acetyl-1-bromo-beta -D-galactopyranosyl chloride when treated with 1.25 equiv silver fluoride in acetonitrile, whereas tetra-O-acetyl-beta -galactopyranosylidene fluoride could be prepared in 54% yield with 3.3 equiv AgF. The gem-difluoride could be deacetylated quantitatively. Upon treatment with 1,4-diazabicyclo[2.2.2] octane, peracetylated 1-bromo-beta -D-galactopyranosyl chloride underwent 1,2-elimination of hydrogen bromide to afford 2,3,4,6-tetra-0-acetyl-D-lyxo-hex-1-enopyranosyl chloride in 33 % yield. (C) 2001 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.

KW - radical bromination of tetra-O-acetyl-beta-D-galactopyranosyl chloride

KW - pyranosylgem-dihalides

KW - sugars

KW - spectroscopy

KW - fluoride

KW - glycals

U2 - 10.1016/S1387-1609(01)01277-4

DO - 10.1016/S1387-1609(01)01277-4

M3 - Article

VL - 4

SP - 611

EP - 617

JO - Comptes Rendus - Academie des Sciences Paris Serie 2 Chimie Fascicule C

JF - Comptes Rendus - Academie des Sciences Paris Serie 2 Chimie Fascicule C

SN - 1387-1609

IS - 7

ER -