Iododediazoniation of Arenediazonium Salts Accompanied by Aryl Radical Ring Closure

Article abstract of DOI:10.1021/jo00386a007

Treatment of o-(allyloxy)benzenediazonium tetrafluoroborate (1a) with sodium iodide in acetone affords the cyclized iodide 2a in good yield by a mechanism involving the generation and exo cyclization of the aryl radical 6a.Other diazonium salts (1b-i) containing suitable unsaturated side chains behave similarly, but those (1l,1m) in which there is an N-allylsulfonamido group yield mainly products formed by endo cyclization.The diazonium salts 1j and 1k do not give cyclized products.Factors affecting the mechanism, rates, and regiochemistry of the reaction are discussed.