Studies on novel synthetic methodologies - Part 45 - Novel and efficient Lewis acids as catalysts for single-step synthesis of pyrano- and furoquinolines

Some Lewis acids such as ZrCl4, SnCl4, TiCl4, and PtC14 have been found to be novel and highly efficient catalysts for one-pot coupling of the three components, anilines, aldehydes, and 3,4-dihydro-2H-pyran or 2,3-dihydrofuran to produce the corresponding pyrano- or furoqinolines in high yields and high diastereoselectivity.