Iron Porphyrin-Catalyzed Olefination of Ketenes with Diazoacetate for the Enantioselective Synthesis of Allenes

In the presence of Ph3P and catalytic Fe(TCP)Cl, ketenes could react with EDA to give allenes in high yields under neutral conditions for the first time. By employing chiral phosphine instead of PPh3, allenes could be synthesized with high enantioselectivity (93−98% ee) in good yields.