“…Our attempt to promote the reaction by adding oxidants (e.g., potassium peroxymonosulfate [5], I 2 [6], MnO 2 [7], and 2,3-dichloro-5,6-dicyanop-benzoquinone (DDQ) [8]), acidic catalysts (e.g., BF 3 ÁEt 2 O [9] and polyphosphoric acid (PPA) [10]), or reducing agents (e.g., SnCl 2 [11]) according to precedent reports failed to generate the desired product. Interestingly, in our search for potential metal catalyst [12], we found that ZrOCl 2 Á8H 2 O and ZrCl 4 exhibited a dramatic catalytic effect on the reactions of 1,2-phenylenediamines with 1 and improved the yields to 50%-70% [3]. However, the understanding of this metal-catalyzed condensation/cyclization reaction is still very limited and the extension of this approach to N,N-dialkylated 3-aminoacroleins has never been explored.…”