One-Step Construction of Tetrahydro-5H-indolo[3,2-c]quinolines from Benzyl Azides and Indoles via a Cascade Reaction Sequence
journal contributionposted on 16.12.2011, 00:00 by Zengqiang Song, Yu-Ming Zhao, Hongbin Zhai
A novel one-step assembly of tetrahydro-5H-indolo[3,2-c]quinolines from benzyl azides and indoles via a formal [4 + 2] cycloaddition is described. A cascade reaction sequence, which involves benzyl azide-to-iminium rearrangement followed by two sequential Pictet–Spengler reactions, generates the tetracycles in moderate to excellent yields. The current method is applicable to a broad substrate scope and holds significant potential in constructing polycyclic indolines with tertiary and/or quaternary carbon centers.