Palladium-catalyzed synthesis of natural and unnatural 2-, 5-, and 7-oxygenated carbazole alkaloids from N-arylcyclohexane enaminones

Molecules. 2013 Aug 26;18(9):10334-51. doi: 10.3390/molecules180910334.

Abstract

A palladium-catalyzed synthesis of the carbazole framework is described, including the preparation of 2-, 5-, and 7-oxygenated natural and unnatural carbazole alkaloids. A series of N-arylcyclohexane enaminones, generated by condensation of cyclohexane-1,3-dione with diverse anilines, were aromatized by a Pd(0)-catalyzed thermal treatment to afford the corresponding diarylamines. The latter were submitted to a Pd(II)-catalyzed cyclization and methylation processes to provide the desired carbazoles, including clausine V. Following an inverse strategy, a new and short total synthesis of glycoborine is also reported.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaloids / chemical synthesis*
  • Carbazoles / chemical synthesis*
  • Catalysis
  • Cyclization
  • Cyclohexanes / chemistry*
  • Palladium / chemistry*

Substances

  • Alkaloids
  • Carbazoles
  • Cyclohexanes
  • Palladium