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.

The Cu‐mediated skeletal rearrangement of O‐propargyl oximes features a mechanistic manifold that yields different compounds. Strategic modification of the substituent at the oxime moiety (R3) allows the selection of a preferred mechanistic route that leads to azete oxides/amidodienes (if R3 is an electron‐poor/‐rich aryl group) or to pyridine N‐oxides (if R3 is an olefin). In the present work, we explore the mechanism that leads to each product. All the computed mechanisms have in common an initial stepwise 2,3‐rearrangement that generates the key N‐allenylnitrone intermediate the further reactivity of which will depend on the nature of the R3 substituent. Our calculations reveal the subtle details that govern the different behavior of this reaction with each of the aforementioned substituents and disclose a complex and multistep pathway to different aminodienes.

Thorough mechanistic investigation unveils details of the allenylation of terminal alkynes (ATA) under Crabbé-like conditions allowing for an enantioselective approach.