Iron-Catalyzed Cross-Coupling of Propargyl Ethers with Grignard Reagents for the Synthesis of Functionalized Allenes and Allenols

Herein we disclose an iron-catalyzed cross-coupling reaction of propargyl ethers with Grignard reagents. The reaction was demonstrated to be stereospecific and allows for a facile preparation of optically active allenes via efficient chirality transfer. Various tri- and tetrasubstituted fluoroalkyl allenes can be obtained in good to excellent yields. In addition, an iron-catalyzed cross-coupling of Grignard reagents with α-alkynyl oxetanes and tetrahydrofurans is disclosed herein, which constitutes a straightforward approach towards fully substituted β- or γ-allenols, respectively.