Atom transfer addition and annulation reactions of propargyl iodomalononitrile

Abstract Heating of propargyl iodomalonitrile with mono-, di- or trisubstituted alkenes followed by reduction of the crude or isolated products with tributyltin hydride produces dicyano(methylene)cyclopentanes in good to excellent overall yield. This radical annulation is often highly regio and stereoselective. The mechanism is discussed.