Stereoselective cycloaddition of dibenzoxazepinium ylides to acetylenes and fullerene C60. Conformational behavior of 3-aryldibenzo[b,f]pyrrolo[1,2-d][1,4]oxazepine systems

J Org Chem. 2010 Aug 6;75(15):5211-5. doi: 10.1021/jo100966j.

Abstract

Cycloaddition of dibenzoxazepinium ylides to acetylene carboxylates leads to cis-3-aryl-3,13b-dihydrodibenzo[b,f]pyrrolo[1,2-d][1,4]oxazepinecarboxylates, which smoothly dehydrogenate to the corresponding pyrrole derivatives. The o-bromophenyl-substituted pyrrole, in contrast to the pyrroline analogue, demonstrates atropoisomerism. Stereoselective cycloaddition of dibenzoxazepinium ylides to fullerene C(60) gives rise to fulleropyrrolidines with cis-configuration. Restricted Ph group rotation is found in the phenyl derivative. Only one of two possible atropoisomers is formed in the reaction of o-bromophenyl-substituted ylide with fullerene C(60). Details of cycloaddition and conformational behavior of cycloadducts were studied by DFT computations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylene / chemistry*
  • Cyclization
  • Fullerenes / chemistry*
  • Magnetic Resonance Spectroscopy
  • Molecular Conformation
  • Oxazepines / chemistry*
  • Spectrometry, Mass, Electrospray Ionization
  • Stereoisomerism

Substances

  • Fullerenes
  • Oxazepines
  • fullerene C60
  • Acetylene