Tuning Secondary-Sphere Lewis Acidity via Late-Stage Modification of an Appended Borane

Alice L Atkins; Matthias Zeller; Nathaniel K Szymczak

doi:10.1021/acs.inorgchem.4c03056

Tuning Secondary-Sphere Lewis Acidity via Late-Stage Modification of an Appended Borane

Inorg Chem. 2024 Dec 2;63(48):22650-22655. doi: 10.1021/acs.inorgchem.4c03056. Epub 2024 Nov 18.

Authors

Alice L Atkins¹, Matthias Zeller², Nathaniel K Szymczak¹

Affiliations

¹ Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.
² H. C. Brown Laboratory, Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.

PMID: 39556512
DOI: 10.1021/acs.inorgchem.4c03056

Abstract

To develop synthetic strategies to construct ligands containing secondary-sphere acids, we demonstrate that an appended borane of low Lewis acidity (-BPin) can be upgraded to a strong Lewis acid (-BF₂). Using a pyridine-pyrazole ligand coordinated to Mo(CO)₄, we show that a pendent -BPin group undergoes exhaustive fluorination to -BF₃K, a precursor to a highly acidic -BF₂ unit (acceptor number ∼15× greater than that of -BPin).