Brønsted Acid Catalysis: Hydrogen Bonding versus Ion Pairing in Imine Activation

Abstract

Behind the scenes: NMR spectroscopy was used to distinguish hydrogen bonding and ion pairing in the activation of imines by a phosphate catalyst (see structures). Hydrogen-bond strength and the amount of the hydrogen-bonded species present are decisive for the catalytic reaction and can be manipulated by introducing substituents with different electronic properties. This insight should guide the development of more efficient catalytic systems. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.