Total synthesis of hamacanthin B class marine bisindole alkaloids
A method for the synthesis of 1-(1 H -indol-3-yl)ethane-1,2-diamines, key synthetic precursors of a number of marine alkaloids, has been developed based on the reduction of adducts of O -benzylhydroxylamine and N -protected 3-(2-nitrovinyl)indoles. For the first time, the total synthesis of 6’,6”-didebromohamacanthin B, 6’-debromohamacanthin B, and 6”-debromohamacanthin B, the secondary metabolites of the sponges Spongosorites and Discodermia calyx , was carried out.