The synthesis of unprecedented BINOL-derived cationic phosphonites is described. Through the use of these phosphanes as ancillary ligands in AuI catalysis, a highly regio- and enantioselective assembly of appropriately designed alkynes into 1-(aryl)benzo[5]carbohelicenes is achieved. The modular synthesis of these ligands and the enhanced reactivity that they impart to AuI -centers after coordination have been found to be the key features that allow an optimization of the reaction conditions until the desired benzo[5]helicenes are obtained with high yield and enantioselectivity.
Keywords: [5]helicenes; asymmetric catalysis; cationic phosphonites; gold catalysis; ligand design.
© 2020 The Authors. Published by Wiley-VCH GmbH.