One-Pot Preparation of Pyranoquinolinones by Ytterbium(III) Trifluoromethanesulfonate-Catalyzed Reactions: Efficient Synthesis of Flindersine, N-Methylflindersine, and Zanthosimuline Natural Products

An efficient synthesis of pyranoquinolinones is achieved by ytterbium(III) triflate-catalyzed reaction of 4-hydroxy-2-quinolones with a variety of α,β-unsaturated aldehydes in moderate yields. This new method has been applied to the synthesis of pyranoquinolinone alkaloids.