DMAP-Promoted Cascade Reaction of α-Ketoester with Benzylidene- Malononitrile: Access Polyfunctionalized 2-Amino-3-Cyano-4H-Pyran Containing Ester Motifs

A base-promoted cascade reaction of α-ketoester with benzylidene-malononitrile was developed under mild reaction conditions, which enabled the synthesis of polyfunctionalized 2-amino- 3-cyano-4H-pyrans containing ester motifs at 6-position with good to excellent yields. These transformations not only construct various polyfunctionalized 4H-pyrans, which add a new member to the family of 4H-pyrans, but also provide an efficient approach for the synthesis of fully substituted 4Hpyran derivatives.