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(sp(3))-H arylation as the key steps. Whereas the C(sp(3))-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.