ol6b01376_si_003.cif (15.44 kB)

Carbazole Annulation via Cascade Nucleophilic Addition–Cyclization Involving 2‑(Silyloxy)pentadienyl Cation

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posted on 03.06.2016, 23:45 by Jacob R. Stepherson, Caitlan E. Ayala, Thomas H. Tugwell, Jeffrey L. Henry, Frank R. Fronczek, Rendy Kartika
We report a new strategy toward the synthesis of highly functionalized carbazoles via 2-(silyloxy)­pentadienyl cation intermediates, which were generated upon ionization of vinyl-substituted α-hydroxy silyl enol ethers under Brønsted acid catalysis. These electrophilic species were found to readily undergo cascade reactions with substituted indoles to generate carbazole molecular scaffolds in good yields via a sequence of regioselective nucleophilic addition, followed by intramolecular dehydrative cyclization.