One-Step, Effective, and Cascade Syntheses of Highly Functionalized Cyclopentenes with High Diastereoselectivity.

Tetrabutylammonium fluoride works as an effective organocatalyst for the cycloaddition between phenacylmalononitriles and electron-deficient olefins (having substituent groups of NO, CHO, and COR), providing a facile synthetic route to versatile multifunctionalized cyclopentenes having an allylic quaternary carbon center bearing both cyano and carboxamide groups with high yields and high diastereoselectivity. Preliminary studies reveal that these functionalized cyclopentenes are convenient precursors for making α-cyano-functionalized cyclopentadienone oximes.