Total Synthesis of (+)-okaramine J featuring an exceptionally facile N-reverse-prenyl to C-prenyl aza-Claisen rearrangement

reaction: see text] The convergent total synthesis of (+)-okaramine J was achieved in a longest linear sequence of 12 steps from l-tryptophan tert-butyl ester. A key reaction was the acid-catalyzed room-temperature aza-Claisen rearrangement of a N-reverse-prenylated hexahydro2,3-b]pyrroloindole to a C-prenylated derivative.