An Arbuzov-type reaction with the bis(alkynyl) iridium complex [Cp*Ir(L)(CCAr)2]

• Reactivity of bis(alkynyl) iridium complexes [Cp*Ir(L)(CCAr)2].
• Arbuzov-type reaction with phosphites to give four-membered iridacyclic phosphonates.
• Acid-catalysed isomerisation to five-membered iridafurans
• Acid-catalysed aerobic oxidation to form 1,2-diketone iridabenzofurans.
• Common reaction pathway involving initial protonation and alkynyl migration.

The bis(alkynyl) iridium complexes [Cp*Ir(L)(CCAr)2] undergo an Arbuzov-type reaction with phosphites to give four-membered iridacyclic phosphonates [Cp*Ir(L){C(Ar)C[P(O)(OR)2]CCHAr}]. These can isomerise to a five-membered iridafuran in the presence of a strong acid. In the absence of a phosphite, the bis(alkynyl) iridium complexes undergo acid-catalysed aerobic oxidation to form 1,2-diketone iridabenzofurans [Cp*Ir(L){C6H4-1,2-CHCC(O)C(O)Ar}]. A common reaction pathway involving initial protonation and alkynyl migration is proposed.

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