Revisiting the effect of f‐functions in predicting the right reaction mechanism for hypervalent iodine reagents

• Published in: Journal of computational chemistry 2021-03, Vol.42 (7), p.470-474
• Main Authors: Sun, Tian‐Yu, Chen, Kai, Zhou, Huakang, You, Tingting, Yin, Penggang, Wang, Xiao
• Format: Article
• Language: English
• Subjects: Chemists; Impact prediction; Iodine; Isomerization; Oxidation; Potential energy; Reaction mechanisms; Reagents
• ISSN: 0192-8651; 1096-987X
• DOI: 10.1002/jcc.26469

To understand the effect of f‐functions in predicting the right reaction mechanism for hypervalent iodine reagents, we adopt the Ahlrichs basis set family def2‐SVP and def2‐TZVP to revisit the potential energy surfaces of IBX‐mediated oxidation and Togni I's isomerisation. Our results further prove that f‐functions (in either Pople, Dunning, or Ahlrichs basis set series) are indispensable to predict the correct rate‐determining step of hypervalent iodine reagents. The f‐functions have a significant impact on the predicted reaction barriers for processes involving the IX (X = O, OH, CF3, etc.) bond cleavage and formation, for example, in the reductive elimination step or the hypervalent twist step. We furthermore explore two hypervalent twist modes that account for the different influences of f‐functions for IBX and Togni I. Our findings may be helpful for theoretical chemists to appropriately study the reaction mechanism of hypervalent iodine reagents. Hypervalent iodine compounds have emerged as versatile and eco‐friendly reagents in organic synthesis and, therefore, correct determination of their reaction determining steps (RDS) is of great importance for scientific and engineering purposes. This research examines the roles of f‐functions in the identification of RDS for two popular hypervalent iodine reagents, that is, 2‐iodoxybenzoic acid and Togni's reagent I. We demonstrate the indispensability of f‐functions in predicting the right RDS and further explore its origins.