Synthesis of Heteroaryl Iodanes(III) via ipso‐Substitution Reactions Using Iodine Triacetate Assisted by HFIP

The synthesis of monoaryl‐λ3‐iodanes generally requires the oxidation of iodoarenes, but the functional group compatibility is often problematic when using oxidizable substrates such as heteroaromatic compounds. Although electrophilic aromatic substitution or ipso‐substitution reactions using iodine tricarboxylates have been studied as an alternative synthetic route to dicarboxyiodoarenes, several common heteroaromatic substrates such as indoles, quinolines, (benzo)furans, and (benzo)thiophenes have not been investigated to date. Here, we report that ipso‐substitution reactions of heteroaromatic stannanes using I(OAc)3 in the presence of 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) effectively provide diacetoxyiodoarenes, which can be converted into the corresponding iodonium ylides or be directly used in a one‐pot iodoarylation reaction. Stay hyper! Heteroaryl iodanes(III) were prepared via ipso‐substitution reactions of heteroarylstannanes using I(OAc)3 in the presence of 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP). Both electron‐rich and electron‐deficient heteroarylstannanes could be used as substrates, and the corresponding iodonium ylides were synthesized in a one‐pot fashion. The present method thus enables the otherwise difficult synthesis of hypervalent iodine(III) compounds.