Three-component aza-Diels–Alder reactions using Yb(OTf)3 catalyst under conventional/ultrasonic techniques

• Aza-Diels–Alder reaction performed under conventional/ultrasonic techniques.
• Ultrasonic irradiation provided higher yields and shorter reaction times.
• Ultrasound-assisted reactions occurred in milder conditions.

The Yb(OTf)3 catalyzed formal aza-Diels–Alder (or Povarov) reaction of cyclopentadiene and 1,3-cyclohexadiene with in situ-generated N-arylimines under conventional/ultrasonic techniques is herein described. This kind of three-component Povarov reaction results in quinoline and phenanthridine derivatives, which are important biological compounds.