Multicomponent Annulative SO2 Insertion of Heteroatom‐Linked 1,7‐Diynes for Accessing Tricyclic Sulfones

Abstract A metal‐free radical multicomponent bicyclization of heteroatom‐linked 1,7‐diynes with aryl diazonium tetrafluoroborates and DABCO‐bis(sulfurdioxide) (DABSO) is reported, enabling annulative SO 2 insertion access to produce two types of skeletally diverse tricyclic sulfones, namely, thieno[3,4‐ c ]quinoline 2,2‐dioxides and thieno[3,4‐ c ]chromene 2,2‐dioxides, with moderate to good yields by simply tuning the linkers of the 1,7‐diynes. This protocol demonstrates remarkable compatibility regarding N ‐ and O ‐linked 1,7‐diynes with different substitution patterns and aryl diazonium tetrafluoroborates. magnified image