Total synthesis of a pyrroloindoloquinazoline alkaloid.

A highly concise stereoselective synthesis of a newly identified alkaloid with a pyrroloindoloquinazoline skeleton has been achieved. To this end, a chiral auxiliary mediated asymmetric acetate aldol reaction on tryptanthrin was explored and the resulting adduct was converted to the product by a novel one-pot reductive cyclization/transamidation using NiCl2·6H2O/NaBH4 in methanol.