Nitrovinylindoles as Heterotrienes: Electrocyclic Cyclization En Route to β-Carbolines: Total Synthesis of Alkaloids Norharmane, Harmane, and Eudistomin N.

Unusual cascade transformation was developed involving microwave assisted electrocyclic cyclization of aci (alkylideneazinic acid) forms of nitrovinylindoles acting as heterotrienes. Subsequent one-pot reduction allowed for efficient access to β-carbolines, including several natural products, alkaloids norharmane, harmane and eudistomin N.