Diastereoselective ZnCl 2 -Mediated Joullié-Ugi Three-Component Reaction for the Preparation of Phosphorylated N -Acylaziridines from 2 H -Azirines.

We disclose a direct approach to the diastereoselective synthesis of phosphorus substituted N -acylaziridines based on a one-pot ZnCl 2 -catalyzed Joullié-Ugi three-component reaction of phosphorylated 2 H -azirines, carboxylic acids and isocyanides. Hence, this robust protocol offers rapid access to an array of N -acylaziridines in moderate-to-good yields and up to 98:2 dr for substrates over a wide scope. The relevance of this synthetic methodology was achieved via a gram-scale reaction and the further derivatization of the nitrogen-containing three-membered heterocycle. The diastereo- and regioselective ring expansion of the obtained N -acylaziridines to oxazole derivatives was accomplished in the presence of BF 3 ·OEt 2 as an efficient Lewid acid catalyst.