Synthesis of the indolo[2,3-a]carbazole natural products staurosporinone and arcyriaflavin B

Abstract
Flexible synthetic routes involving double nitrene insertions are described leading to the indolo[2,3-a]carbazole systems present in a growing group of natural products. The methods are exemplified by the total synthesis of two members of this group staurosporinone (9; R = H) and arcyriaflavin B (2).