Rhodium-Catalyzed Tandem C-H Annulation Enabled by Transient Directing Group Strategy and Sequential Nucleophilic Substitution.

A novel protocol of rhodium-catalyzed tandem C-H annulation of aldehyde and aniline with diazonaphthalen-1(2)-one via transient directing group strategy and sequential nucleophilic substitution has been demonstrated in moderate to excellent yields. This reaction proceeds smoothly via intramolecular cyclization to form 6-benzo[]chromen-6-ol and is followed by nucleophilic substitution of -carbon of aniline to construct 6-aryl-6-benzo[]chromene derivatives. A series of 6-aryl-6-benzo[]chromenes were synthesized in one-pot via the tandem C-H annulation.