Researcher ORCID Identifier
0000-0002-6816-1113
Document Type
Article
Department
Chemistry (Pomona)
Publication Date
6-12-2022
Keywords
Anions, calcium bistriflimide, S(VI) fluoride, SuFEx, computational chemistry, transition states, kinetics, catalysis
Abstract
We report a mechanistic investigation of calcium bistriflimide-mediated sulfur(VI)–fluoride exchange (SuFEx) between sulfonyl fluorides and amines. We determine the likely pre-activation resting state─a calcium bistriflimide complex with ligated amines─thus allowing for corroborated calculation of the SuFEx activation barrier at ∼21 kcal/mol, compared to 21.5 ± 0.14 kcal/mol derived via kinetics experiments. Transition state analysis revealed: (1) a two-point calcium-substrate contact that activates the sulfur(VI) center and stabilizes the leaving fluoride and (2) a 1,4-diazabicyclo[2.2.2]octane additive that provides Brønsted-base activation of the nucleophilic amine. Stable Ca–F complexes upon sulfonamide formation are likely contributors to inhibited catalytic turnover, and a proof-of-principle redesign provided evidence that sulfonamide formation is feasible with 10 mol % calcium bistriflimide.
Terms of Use & License Information
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License
DOI
10.1021/acs.inorgchem.2c01230
Recommended Citation
Ball, Nicholas; Han, Brian; Khasnavis, Samuel R.; Nwerem, Matthew; Bertagna, Michael; and Ogba, O Maduka, "Calcium Bistriflimide-Mediated Sulfur (VI)–Fluoride Exchange (SuFEx): Mechanistic Insights toward Instigating Catalysis" (2022). Pomona Faculty Publications and Research. 492.
https://scholarship.claremont.edu/pomona_fac_pub/492
