α‐Aryliodonio Diazo Compounds: SN Reactions at the α‐C Atom as a Novel Reaction Type for Diazo Compounds

α-Onio-substituted diazo compounds 2 are formed by reaction of nucleophiles Nu with α-aryliodonio diazo compounds such as 1. These are the first SN reactions at the α-C atom of diazo compounds that proceed with retention of the diazo function. Nu = pyridine, SMe2, AsPh3, SbPh3, NEt3.