Efficient iron-mediated approach to pyrano[3,2-a]carbazole alkaloids--first total syntheses of O-methylmurrayamine A and 7-methoxymurrayacine, first asymmetric synthesis and assignment of the absolute configuration of (-)-trans-dihydroxygirinimbine.

@article{Gruner2011EfficientIA,
  title={Efficient iron-mediated approach to pyrano[3,2-a]carbazole alkaloids--first total syntheses of O-methylmurrayamine A and 7-methoxymurrayacine, first asymmetric synthesis and assignment of the absolute configuration of (-)-trans-dihydroxygirinimbine.},
  author={Konstanze K. Gruner and Thomas Hopfmann and Kazuhiro Matsumoto and Anne J{\"a}ger and Tsutomu Katsuki and Hans‐Joachim Kn{\"o}lker},
  journal={Organic \& biomolecular chemistry},
  year={2011},
  volume={9 7},
  pages={
          2057-61
        }
}
Iron-mediated oxidative cyclisation provides an efficient approach to pyrano[3,2-a]carbazole alkaloids. Thus, improved routes to girinimbine and murrayacine as well as the first total syntheses of O-methylmurrayamine A and 7-methoxymurrayacine are reported. Asymmetric epoxidation of girinimbine led to (-)-trans-dihydroxygirinimbine and the assignment of its absolute configuration. 
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