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Total Synthesis of the Biscarbazole Alkaloids Murrafoline A–D by a Domino Sonogashira Coupling/Claisen Rearrangement/Electrocyclization Reaction


  • Part 110 of “Transition Metals in Organic Synthesis”; for part 109, see: Ref. 8. We are grateful to the Alexander von Humboldt Foundation (fellowship to V.P.K.) and the Deutsche Forschungsgemeinschaft (grant KN 240/16-1) for financial support. We thank Regina Czerwonka and Nils Richter for experimental support.


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Why take things one step at a time? Aryl–pyran-linked biscarbazole alkaloids of the murrafoline group (see crystal structure of murrafoline A; dark gray: C, red: O, blue: N) were accessed readily by a novel domino reaction sequence involving Sonogashira coupling, a Claisen rearrangement, and electrocyclization. The one-pot procedure enables the straightforward synthesis of these structurally challenging alkaloids in only a few steps.