The Outer-Sphere Mechanism of Nitrene Transfer onto Gold(I) Alkyne Complexes

The recently developed nitrene transfer reaction onto gold-activated alkynes provides a route to safe and accessible synthons of α-diazo imides. This reaction is rather unique in that it requires AuI in catalytic amounts; however, this promiscuous metal is only used to activate the alkyne moiety. After such activation is obtained, the nitrene-transfer process occurs through an outer-sphere mechanism, in which the metal acts only as a spectator. Density functional theory was applied to elucidate this peculiar reaction and to provide a mechanistic explanation for the experimentally observed isomers at the double bond and imine sites.