Practical and modular cycloadditions of in-situ formed exocyclic vinylcarbenes

The exploration of reactive intermediates, which enable chemo- and regioselective cycloaddition reactions for the expeditious construction of fused and/or bridged ring systems, continues to draw a great deal of interest from the synthetic community. Vinylcarbene species, which serve as 3-carbon building blocks, have been frequently used for the construction of (hetero)cyclic frameworks through the successive formation of multiple carbon–carbon and/or carbon–heteroatom bonds. Herein, we report a concise strategy for the catalytic generation of an exocyclic α-vinyl gold carbene species via a selective gold(I)-promoted azide-enyne cyclization process. Subsequently, practical and modular cycloadditions of these in-situ-formed intermediates with different types of partners were disclosed, producing a diverse array of fused and bridged pyrroles in high chemo-, regio-, and stereoselectivity.