Fragmentation of carbohydrate anomeric alkoxyl radicals: new synthesis of chiral 1-fluoro-1-halo-1-iodoalditols

C.G. Francisco, C.C. Gonzalez, A.R. Kennedy, N.R. Paz, E. Suarez

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Anew general methodology for the synthesis of 1,1,1-trihaloalditols by starting from 1,5-anhydro-2-deoxyhex- 1-enitol derivatives (glycals) is described. The halogens are introduced sequentially in each of the three different steps of the process. The fluorine is introduced in the first step by electrophilic fluorination of the starting glycal; next, hydroxyhalogenation of the resulting vinyl fluoride allows the addition of any halogen (F, Cl, Br or I) at will, and finally, an iodine atom is inserted through an alkoxyl radical fragmentation reaction. This methodology allows the preparation of diverse types of 1,1,1-trihalogenated compounds (R CF2I, RCFI2, RCFClI and R CFBrI) under mild conditions compatible with sensitive substituents. In some cases, the diastereomeric mixtures generated from RCFClI and RCFBrI can be chromatographically separated, and their configuration determined by X-ray crystallographic analysis. The synthetic usefulness of these compounds has been preliminarily assessed by examining the reactivity of the fluorinated radical generated by rupture of the CI bond.
Original languageEnglish
Pages (from-to)6704-6712
Number of pages8
JournalChemistry - A European Journal
Volume14
Issue number22
DOIs
Publication statusPublished - 2008

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Halogens
Carbohydrates
Iodine
Fluorine
Derivatives
Atoms
alkoxyl radical
vinyl fluoride

Keywords

  • alditols
  • asymmetric synthesis
  • carbohydrates
  • halogens
  • radical reactions

Cite this

Francisco, C.G. ; Gonzalez, C.C. ; Kennedy, A.R. ; Paz, N.R. ; Suarez, E. / Fragmentation of carbohydrate anomeric alkoxyl radicals: new synthesis of chiral 1-fluoro-1-halo-1-iodoalditols. In: Chemistry - A European Journal. 2008 ; Vol. 14, No. 22. pp. 6704-6712.
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Fragmentation of carbohydrate anomeric alkoxyl radicals: new synthesis of chiral 1-fluoro-1-halo-1-iodoalditols. / Francisco, C.G.; Gonzalez, C.C.; Kennedy, A.R.; Paz, N.R.; Suarez, E.

In: Chemistry - A European Journal, Vol. 14, No. 22, 2008, p. 6704-6712.

Research output: Contribution to journalArticle

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AU - Francisco, C.G.

AU - Gonzalez, C.C.

AU - Kennedy, A.R.

AU - Paz, N.R.

AU - Suarez, E.

PY - 2008

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N2 - Anew general methodology for the synthesis of 1,1,1-trihaloalditols by starting from 1,5-anhydro-2-deoxyhex- 1-enitol derivatives (glycals) is described. The halogens are introduced sequentially in each of the three different steps of the process. The fluorine is introduced in the first step by electrophilic fluorination of the starting glycal; next, hydroxyhalogenation of the resulting vinyl fluoride allows the addition of any halogen (F, Cl, Br or I) at will, and finally, an iodine atom is inserted through an alkoxyl radical fragmentation reaction. This methodology allows the preparation of diverse types of 1,1,1-trihalogenated compounds (R CF2I, RCFI2, RCFClI and R CFBrI) under mild conditions compatible with sensitive substituents. In some cases, the diastereomeric mixtures generated from RCFClI and RCFBrI can be chromatographically separated, and their configuration determined by X-ray crystallographic analysis. The synthetic usefulness of these compounds has been preliminarily assessed by examining the reactivity of the fluorinated radical generated by rupture of the CI bond.

AB - Anew general methodology for the synthesis of 1,1,1-trihaloalditols by starting from 1,5-anhydro-2-deoxyhex- 1-enitol derivatives (glycals) is described. The halogens are introduced sequentially in each of the three different steps of the process. The fluorine is introduced in the first step by electrophilic fluorination of the starting glycal; next, hydroxyhalogenation of the resulting vinyl fluoride allows the addition of any halogen (F, Cl, Br or I) at will, and finally, an iodine atom is inserted through an alkoxyl radical fragmentation reaction. This methodology allows the preparation of diverse types of 1,1,1-trihalogenated compounds (R CF2I, RCFI2, RCFClI and R CFBrI) under mild conditions compatible with sensitive substituents. In some cases, the diastereomeric mixtures generated from RCFClI and RCFBrI can be chromatographically separated, and their configuration determined by X-ray crystallographic analysis. The synthetic usefulness of these compounds has been preliminarily assessed by examining the reactivity of the fluorinated radical generated by rupture of the CI bond.

KW - alditols

KW - asymmetric synthesis

KW - carbohydrates

KW - halogens

KW - radical reactions

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