Modular Access to Tetrasubstituted Allenes via 1,4-Dialkylation of 1,3-Enynes

Herein, a cobalt-catalyzed highly regio- and chemoselective 1,4-dialkylation of 1,3-enynes using readily available fluoroalkyl halides and solid alkylzinc pivalates is disclosed. This ligand-free protocol proceeds under mild conditions and tolerates a wide range of functional groups, including aryl, alkyl, and silyl substituents on the enynes, diverse primary alkylzinc reagents, and various fluoroalkyl halides (monofluoro-, difluoro-, perfluoro-, and bromo-containing derivatives), thus providing a complementary and practical access to structurally diverse fluoroalkylated allenes, expanding the toolbox for allene synthesis and showing potential for drug discovery in medicinal chemistry.