Total syntheses of (−)-vallesamidine and related Aspidosperma and Hunteria type indole alkaloids from the common intermediate

A new synthetic method of (−)-vallesamidine, including a unique 2,2,3-trialkylindoline skeleton, was developed by reductive radical cyclization reaction from the 2,3-dialkylindole derivative, which has been known to be an intermediate for the synthesis of aspidospermidine.