Synthesis of the cycloheptannelated indole fragment of dragmacidin E

Synthesis of the pivotal cycloheptannelated indole fragment of indole alkaloid dragmacidin E is achieved. The synthesis features a Pd-catalyzed indole synthesis reaction for the preparation of 3,7-disubstituted indole, a regioselective intramolecular Friedel–Crafts reaction for the construction of the 3,4-bridged cycloheptannelated indole skeleton, and a coupling reaction of vinyl triflate with diorganocuprate.