(4+3) annulation of enone-tethered indoles with α-alkylidene succinimides: access to seven-membered azepino[3,2,1-<i>hi</i>]indole scaffolds

We have developed a straightforward synthesis of azepino[3,2,1-<i>hi</i>]indole architectures with four contiguous chiral carbons as single diastereomers. This metal-free protocol between indole-enones and alkylidene succinimides proceeds efficiently under ambient conditions, demonstrating a broad scope in good to excellent yields. The feasibility of the current methodology was illustrated by one-pot, gram-scale synthesis and further modifications.