Asymmetric Total Synthesis of (+)-Dragmacidin D Reveals Unexpected Stereocomplexity

Abstract

The first asymmetric total synthesis of the bis-indole marine alkaloid (+)-dragmacidin D (1) has been achieved. This synthesis revises an earlier configurational assignment based on biosynthetic considerations and assigns an R absolute configuration to (+)-1. The current studies reveal that natural dragmacidin D is isolated as either a racemate or a scalemic mixture (39% ee).