Iron-catalyzed Cross-Coupling of Propargyl Carboxylates and Grignard Reagents: Synthesis of Substituted Allenes

Presented herein is a mild, facile, and efficient iron-catalyzed synthesis of substituted allenes from propargyl carboxylates and Grignard reagents. Only 1-5mol% of the inexpensive and environmentally benign [Fe(acac)(3)] at -20 degrees C was sufficient to afford a broad range of substituted allenes in excellent yields. The method tolerates a variety of functional groups.