Synthesis of Tricyclic Nitrogen Heterocycles by a Sequence of Palladium-Catalyzed N–H and C(sp3)–H Arylations

A range of tricyclic nitrogen heterocycles were synthesized in a straightforward and efficient manner via a sequence involving palladium-catalyzed N-arylation and C(sp3)–H arylation as the key steps. Whereas the C(sp3)–H arylation furnished fused 6,5,6-membered ring systems efficiently, the formation of the more strained 6,5,5-membered systems proved to be more challenging and required a subtle adjustment of the reaction conditions.