An unexpected phosphine-catalyzed [3+2] annulation. Synthesis of highly functionalized cyclopentenes

An unexpected phosphine-catalyzed [3 + 2] annulation from electron-deficient allenes and substituted alkylidenemalononitriles was realized in which the allylic moiety of the substituted alkylidenemalononitriles served as the three carbon unit of the cyclopentenes instead of the electron-deficient allenes.