Front Cover Picture: Chiral Binaphthyl‐Based Iodonium Salt (Hypervalent Iodine(III)) as Hydrogen‐ and Halogen‐Bonding Bifunctional Catalyst: Insight into Abnormal Counteranion Effect and Asymmetric Synthesis of N,S‐Acetals (Adv. Synth. Catal. 6/2022)

Abstract

The front cover picture, prepared by Dr Y. Yoshida, illustrates the asymmetric syntheses of N,S-acetals catalysed by their originally-designed chiral iodonium salts. The 1,2-addition reaction of bulky thiols to isatin-derived ketimines were catalysed by the chiral iodonium salts in excellent yields and enantioselectivities under neutral conditions. The reaction mechanism was studied using NMR experiments and DFT calculations of a plausible intermediate, which revealed that the imine substrate was activated by the catalyst in a hydrogen- and halogen-bonding bidentate activation manner. Details can be found in the Research Article by Yoshida and co-workers. (Y. Yoshida, T. Fujimura, T. Mino, M. Sakamoto, Adv. Synth. Catal. 2022, 364, 1091-1097; DOI: 10.1002/adsc.202101380)