Neighboring group participation in the additions of iodonium and bromonium ions to N-alkoxycarbonyl-2-azabicyclo[2.2.n]alk-5-enes (n = 1,2)

J Org Chem. 2008 Mar 21;73(6):2114-21. doi: 10.1021/jo702153q. Epub 2008 Feb 22.

Abstract

Additions of iodonium-X reagents to N-alkoxycarbonyl-2-azabicyclo[2.2.1]hept-5-enes and the homologous 2-azabicyclo[2.2.2]oct-5-enes have been found to mirror the outcomes of additions of bromonium-X reagents. Only rearranged products were observed for reactions of either of these halonium ion reagents with the azabicylo[2.2.1]hept-5-enes. For the azabicyclo[2.2.2]oct-5-enes, nitrogen participation in addition of IOH or BrOH was dependent on the N-alkoxycarbonyl group. With larger N-Boc, N-Cbz, or N-Troc protecting groups, unrearranged 5-anti-hydroxy-6-syn-I(or Br)-2-azabicyclo[2.2.2]octanes were formed by nucleophilic attack at C(5) on syn-halonium ions. The structure of N-methyl-8-anti-bromo-4-anti-hydroxy-2-azabicyclo[3.2.1]octane has been reassigned by X-ray analysis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Azabicyclo Compounds / chemistry*
  • Bromine Compounds / chemistry
  • Cycloparaffins / chemistry*
  • Iodine Compounds / chemistry
  • Magnetic Resonance Spectroscopy
  • Onium Compounds / chemistry*

Substances

  • Azabicyclo Compounds
  • Bromine Compounds
  • Cycloparaffins
  • Iodine Compounds
  • Onium Compounds