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Lewis acid catalyzed asymmetric halohydrin reactions of chiral α,β-unsaturated carboxylic acid derivatives withN-halosuccinimide (NXS) as the halogen source

Authors
Journal
Tetrahedron Letters
0040-4039
Publisher
Elsevier
Publication Date
Volume
46
Issue
17
Identifiers
DOI: 10.1016/j.tetlet.2005.03.014
Keywords
  • Lewis Acid
  • Catalyst
  • Asymmetric
  • Halohydrin
  • Halohydroxylation
  • Halomethoxylation
  • N-Halosuccinimide (Nxs)
  • (2R)-N-Enoylbornanesultam
  • α-Halo-β-Hydroxy/Methoxycarboxylic Acid Derivatives

Abstract

Abstract Lewis acid catalyzed asymmetric halohydrin reactions—(halohydroxylation as well as halomethoxylation) of chiral α,β-unsaturated carboxylic acid derivatives were performed using N-halosuccinimide (NXS; X = Br, I) as the halogen source. Regio- and anti-selectivity of 100% and moderate to good diastereoselectivity with good yields were observed when Oppolzer’s sultam was used as the chiral auxiliary. Among the Lewis acids, Yb(OTf) 3 was found to be the best catalyst. Alkenoyl and cinnamoyl substrates smoothly underwent bromohydrin reactions and the more electron-rich cinnamoyl substrates preferred to undergo iodohydrin reactions. However, electron-deficient cinnamoyl substrates did not respond to this Lewis acid catalyzed halohydrin reaction with NXS (X = Cl, Br, I).

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