Access to Polycyclic Azepino[5,4,3-<i>cd</i>]indoles via a Gold-Catalyzed Post-Ugi Dearomatization Cascade

Abstract

The development of a rapid and diverse access to complex natural product-like 3,4-fused indole scaffolds has always attracted considerable attention from synthetic and medicinal communities. We herein disclose a modular and straightforward protocol to prepare the densely substituted polycyclic azepino[5,4,3-<i>cd</i>]indole scaffolds. This synthetic process involves an Ugi four-component reaction from easily available starting materials and a gold-catalyzed post-Ugi domino dearomatization/Michael addition sequence, enabling facile access to the highly functionalized azepino[5,4,3-<i>cd</i>]indole core with excellent chemo-, regio-, and diastereoselectivity.