Synthesis of 2,6,7-Trisubstituted Prenylated indole.

Prenylated indole alkaloids bearing more than one prenyl or reverse-prenyl group show various biological activities. Among them, synthesis of trisubstituted-type prenylated indoles have not been well explored because of the difficulty in regioselective introduction of multiple prenyl and reverse-prenyl groups due to steric hindrance problems. Herein, we describe a synthesis of 2,6,7-trisubstituted prenylated indole using aza-Claisen rearrangement under mild conditions to introduce a prenyl group at C7 in the presence of the prenyl group at C6.