Competition between two intramolecular domino Knoevenagel hetero Diels–Alder reactions: a new entry into novel pyranoquinolinone derivatives

4-Hydroxy-1,2-dihydro-2-quinolinones undergo facile intramolecular domino Knoevenagel hetero Diels–Alder reactions with o-prenylated aromatic aldehydes and the aliphatic aldehyde citronellal, to afford novel pyranoquinolinone derivatives. A high degree of chemoselectivity has been achieved under microwave irradiation condition.