Insight into the Mechanisms of the Multicomponent Ugi and Ugi–Smiles Reactions by ESI‐MS(/MS)

Abstract

AbstractThe mechanisms of the Ugi and Ugi–Smiles reactions were investigated by using finely selected reaction conditions that allowed all of the intermediates to be “fish‐out” and characterized by ESI‐MS/MS. New insight into the Ugi and Ugi–Smiles reaction mechanisms is provided without using charge‐tagged reagents. Characterization of the isomeric species of the Mumm rearrangement in the gas phase was performed by using MS/MS.