10.1021/ol0522081.s001 Ken S. Feldman Ken S. Feldman Paiboon Ngernmeesri Paiboon Ngernmeesri Dragmacidin E Synthesis Studies. Preparation of a Model Cycloheptannelated Indole Fragment American Chemical Society 2005 Dragmacidin E Synthesis Studies Witkop cyclization Key reactions indole nucleus dragmacidin E 10 steps Model Cycloheptannelated Indole Fragment Dieckmann cyclization cycloheptanoid ring tetracyclic cycloheptannelated indole model compound 2005-11-24 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Dragmacidin_E_Synthesis_Studies_Preparation_of_a_Model_Cycloheptannelated_Indole_Fragment/3255538 The conversion of <i>N</i>-2,2-dichloropropionyl indole methyl ester into a tetracyclic cycloheptannelated indole model compound for the synthesis of dragmacidin E was accomplished in 10 steps. Key reactions include a Witkop cyclization to fashion a C−C bond at C(4) of the indole nucleus and a subsequent Dieckmann cyclization to deliver the desired cycloheptanoid ring.