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An efficient method for the synthesis of substituted quinolines is described. By FeCl3-promoted C–C bond formation, 2,3-disubstituted and 2,3,4-trisubstituted quinolines were successfully synthesized from the reaction between imines and electron-deficient alkynes in good yields. The reaction can also be performed in a sequential three-component manner by using aromatic amines and aromatic aldehydes instead of the corresponding imines.

An interesting approach to functionalized imidazolidines is described. These compounds are obtained in a copper(I)-catalyzed domino three-component coupling and cyclization reaction involving two formaldehyde-derived imine units and a terminal alkyne. Alternatively, imidazolidines can be obtained from propargylamines and formaldehyde-derived imines. This strategy provides a straightforward and atom-economic pathway to construct imidazolidines with high yields and benefits from readily available starting materials, convenient one-pot operations.

The required imines may be prepared in situ, thus affording the products in a sequential three-component reaction.

Transformation of (I) with phenyl or trimethylsilylacetylene, respectively, leads to propargylamine intermediates instead of the desired imidazolidines.

A three-component reaction of one molecule of imine and two molecules of alkynoates is realized with the catalysis of Cu(I)–Fe(III) in a sequential manner to allow the direct synthesis of functionalized pyrroles, during which, one C–N bond and two C–C bonds are formed with high atom economy. This method benefits from easily available starting materials, low-cost catalysts, and convenient operations.