Diastereoselective Synthesis of 1,3-Oxazolidines via Cationic Iron Porphyrin-catalyzed Cycloaddition of Aziridines with Aldehydes.

An efficient iron porphyrin Lewis acid-catalyzed cycloaddition of aziridines with aldehydes has been developed to provide oxazolidines with high regio- and diastereoselectivity. The cycloaddition proceeds in toluene with 1 mol % of the iron catalyst at 25 °C. A theoretical study and synchrotron-based X-ray absorption fine structure measurements provided fundamental insights into the aziridine-iron porphyrin complex, which is the key intermediate for the generation of the 1,3-dipole synthon.