Synthesis of Tryptamines through a Novel Bronsted Acid Mediated Tandem Reaction Initiated by α-Iminol Rearrangement of Transient 2-Substituted 2-Hydroxycyclobutylimines

A novel Bronsted acid promoted condensation reaction between a primary aniline and 2-hydroxycyclobutanone provides access to diverse tryptamine derivatives in moderate to good yields. The proposed mechanism involves an α-iminol rearrangement, ring expansion, ring closure, and a depart-And-return rearrangement process.