“…Although a wide range of methodologies for the synthesis of functionalized cyclopentenones exist, the Lewis acid catalyzed transformation of furfural using Sc(OTf) 3 , Dy(OTf) 3 , AlCl 3 , ErCl 3 ·6H 2 O, p- toluenesulfonamide, BF 3 ·OEt 2 , or a heteronuclear 3d/Dy(III) cluster is especially efficient and practical. Moreover, the proposed mechanism for this transformation is very interesting for educational purposes. , On the basis of this facile transformation of furfural ( 1 ) into cyclopentenones with Lewis acids, an undergraduate laboratory experiment, catalyzed by ErCl 3 ·6H 2 O, was developed using the environmentally friendly solvent ethanol (Scheme ).…”