Under microwave irradiation and solvent-free conditions, rare-earth metal chlorides (RECl₃) have been efficient catalysts for one-pot synthesis of quinoline derivatives to give products in good to excellent yields through the multi-component reactions of aldehydes, amines, and alkynes. The rare-earth metal chlorides can be recycled for six times without notable loss of catalytic activities. This new synthetic approach has prominent features of a short reaction time, high yields of products, operational simplicity, broad substrate scopes, environmentally friendly property and commercially available catalysts. It extends the applications of rare-earth metal compounds as catalysts in organic synthesis.

In the presence of 10 mol% lanthanide amide [(Me₃Si)₂N]₃Ln(µ-Cl)Li(THF)₃, the aza-Henry reaction of N-tosyl imines with nitroalkanes (1:5 molar ratio) could be performed in good yields. The lanthanide amide-catalyzed aza-Henry reaction has the features of mild reaction conditions, tolerance of a variety of aromatic aldehyde-derived imines and nitroalkanes, short time and good chemical yields. A catalytic mechanism for the reaction was also proposed.