Regioselective and Diastereoselective Dearomative Multifunctionalization of In-Situ-Activated Azaarenes: An Access to Bridged Azaheterocycles.

Reported herein is an unprecedented multicomponent one-pot dearomative multifunctionalization of commercially available azaarenes through an in situ activation strategy, which not only achieved the first full exploitation of the reactive sites of the azaarenes, but also accomplished the efficient synthesis of bridged hydrogenated pyridines and (iso)quinolines in a highly regioselective and diastereoselective manner. In addition, we could successfully realize the step-controlled dearomative trifunctionalization and bifunctionalization of quinolines.

Diastereoselective construction of 4-indole substituted chromans bearing a ketal motif through a three-component Friedel-Crafts alkylation/ketalization sequence.

The first TfOH-catalyzed three-component Friedel-Crafts alkylation/ketalization sequence of indoles, alcohols and ortho-hydroxychalcones was developed to afford a wide range of 4-indole substituted chromans bearing a ketal motif in 77-99% yields. Notably, only a simple filtration was needed to purify them. By altering methanol to CHCl3, 2,4-bisindole substituted chroman with the same indole substituent at the C2 and C4 positions was afforded. Moreover, 2,4-bisindole substituted chromans with different indole substituents could be obtained by treatment of 4-indole monosubstituted chromans with another indole molecule.