An Aza-Wittig Route to Imidazolines and Imidazoles

Significance

Arndt and co-workers have reported a simple and efficient synthesis of chiral imi­dazolines 4 via a sulfonamide N-acylation and subsequent intramolecular aza-Wittig cyclization strategy. A range of amino acid based acylating agents are tolerated in the amide bond-forming reaction to give 3 in excellent yield with no race­mization observed under the reaction conditions. Ring closure to the imidazolines 4 was achieved without incident upon treatment with Ph₃P. Oxidation to the corresponding imidazoles 5 using a mixture of DBU and BrCCl₃ was demonstrated in a few cases.