Cover Feature: Breslow Intermediates (Amino Enols) and Their Keto Tautomers: First Gas‐Phase Characterization by IR Ion Spectroscopy (Chem. Eur. J. 8/2021).

Cover Feature: Breslow Intermediates (Amino Enols) and Their Keto Tautomers: First Gas-Phase Characterization by IR Ion Spectroscopy (Chem. Eur. J. 8/2021) Keywords: Breslow intermediate; density functional calculations; IR spectroscopy; mass spectrometry; umpolung EN Breslow intermediate density functional calculations IR spectroscopy mass spectrometry umpolung 2552 2552 1 02/08/21 20210205 NES 210205 B Breslow Intermediates b are of pivotal importance for chemical and biological Umpolung reactions catalyzed by N-heterocyclic carbenes (NHCs). The enol-ketone tautomerism of a number of NHC-aldehyde combinations, crucial for their chemical reactivity, have been determined in the gas-phase and interpreted by DFT calculations. [Extracted from the article]