Iodine-Mediated Cyclization of Enamines to Imidazole-4-Carboxylic Derivatives with Sequential Removal of Nitrogen Atoms from TMSN3.

An iodine-mediated oxidative [4+1] cyclization of enamines with TMSN3 for the synthesis of 2,5-disubstituted imidazole-4-carboxylic derivatives has been developed. The mechanistic studies revealed that the reaction proceeds through a sequential removal of two nitrogen atoms from TMSN3. The synthetic utility was further demonstrated with a gram-scale reaction and various derivatization transformations of the products.