Novel syntheses of murrayaquinone A and furostifoline through 4-oxygenated carbazoles by allene-mediated electrocyclic reactions starting from 2-chloroindole-3-carbaldehyde

Chem Pharm Bull (Tokyo). 2001 Jul;49(7):881-6. doi: 10.1248/cpb.49.881.

Abstract

The formal total synthesis of murrayaquinone A (1) and the total synthesis of furostifoline (5) were completed by the construction of 4-oxygenated 3-methylcarbazoles 7 based on a new type of electrocyclic reaction through 2-alkenyl-3-allenylindole intermediates 8 derived from the 2-alkenyl-3-propargylindoles 9, starting from 2-chloroindole-3-carbaldehyde (11). The N,O-bisbenzyloxymethyl group of 16c and 22 underwent a Birch reduction followed by treatment with Triton B to produce the known 4-hydroxy-3-methylcarbazole (7a) and 4-hydroxy-3-methylfuro[3,2-a]carbazole (7b) as precursors of murrayaquinone A (1) and furostifoline (5), respectively. The trifluoromethanesulfonyloxy-3-methylfuro[3,2-alcarbazole (24), prepared from 7b, was subjected to reductive cleavage to provide furostifoline (5).

MeSH terms

  • Alkaloids / chemical synthesis*
  • Benzoquinones / chemical synthesis*
  • Carbazoles / chemical synthesis*
  • Carbazoles / chemistry*
  • Electrochemistry
  • Furans / chemical synthesis*
  • Indicators and Reagents
  • Magnetic Resonance Spectroscopy
  • Spectrometry, Mass, Electrospray Ionization
  • Spectroscopy, Fourier Transform Infrared

Substances

  • Alkaloids
  • Benzoquinones
  • Carbazoles
  • Furans
  • Indicators and Reagents
  • murrayaquinone A
  • furostifoline