Stereoselective transformation of indole diazabicyclo[3.2.2]nonedione to azepinoindole.

[reaction: see text] The synthesis of an indole diazabicyclo[3.2.2]nonedione derivative was achieved in a few steps starting from L-tryptophan. Reduction with borane-THF complex leads to fragmentation of the bicycle and the stereoselective formation of an azepinoindole derivative was observed.