Total syntheses of the slime mold alkaloid arcyriacyanin A

Arcyriacyanin A ( 1 ) has been synthesized by three different routes. In the first synthesis the bisbromomagnesium salt of 2,4′‐biindole ( 5 ) was treated with dibromomaleimide ( 6 ) to yield arcyriacyanin A ( 1 ). The second approach used an intramolecular Heck reaction for the cyclization of a 4‐(triflyloxy)arcyriarubin 8 to N ‐methylarcyriacyanin A ( 2 ). Thirdly, compound 2 was obtained by a domino Heck reaction between 3‐bromo‐4‐[1‐( tert ‐butoxycarbonyl)indol‐3‐yl]‐1‐methylmaleimide ( 9 ) and 4‐bromoindole ( 10 ). The N ‐methyl derivative 2 could be transformed into arcyriacyanin A ( 1 ) by standard methods.