Abstract
Total synthesis of neoechinulin (1) was achieved. 4-(3, 3-Dimethylallyl)-2-nitroaniline (3) was synthesized from N-(3, 3-dimethylallyl)-2-nitroaniline (2) in one step (22% yield) by the acid-catalyzed amino-Claisen rearrangement. The nitroaniline (3) was converted in two steps (45% overall yield) to 5-(3, 3-dimethylallyl)-2-iodoaniline (5), which was condensed with copper acetilide (7) to afford 2-(1, 1-dimethylallyl)-6-(3, 3-dimethylallyl)-indole (6) in 94% yield. The indole (6) was synthesized in better overall yield by another route. Neoechinulin (1) was obtained from 6 in two steps (50% overall yield). Based on these results of the codensation reaction between 11 and 12, the stereochemistry of neoechinulin (1) was discussed.
