An asymmetric iodolactonization reaction catalyzed by a zinc bis-proline-phenol complex

The intramolecular zinc bis-proline-phenol complex 2a was found to promote enantioselective iodolactonization reactions of both electron-rich and electron-poor 5-aryl-5-hexenoic acids affording delta-iodolactones in good chemical yields with up to 82% enantiomeric excess. The reactions were found to be insensitive to air and moisture, providing an experimentally simple protocol for synthetically useful compounds. (C) 2013 Elsevier Ltd. All rights reserved.