Aminoindolines versus quinolines: mechanistic insights into the reaction between 2-aminobenzaldehydes and terminal alkynes in the presence of metals and secondary amines.

DFT computational studies in the cyclization of aminoalkyne (see structure), which is generated in situ by 2-aminobenzaldehydes and terminal alkynes in the presence of metals and secondary amines, has been investigated. The study revealed that the mode of cyclization (exo vs endo) depends on the protecting group on nitrogen, the oxidation state of copper, and substitution on alkyne.