Nickel‐Catalyzed Sulfonylation of Aryl Bromides Enabled by Potassium Metabisulfite as a Uniquely Effective SO<sub>2</sub> Surrogate
J. Caleb Hethcox, Heather C. Johnson, Jungchul Kim, Xiao Wang, Lili Cheng, Yang Cao, Mélissa Tan, Daniel A. DiRocco, Yining Ji
Abstract
Abstract The development and mechanistic investigation of a nickel‐catalyzed sulfonylation of aryl bromides is disclosed. The reaction proceeds in good yields for a variety of substrates and utilizes an inexpensive, stench‐free, inorganic sulfur salt (K 2 S 2 O 5 ) as a uniquely effective SO 2 surrogate. The active oxidative addition complex was synthesized, isolated, and fully characterized by a combination of NMR spectroscopy and X‐ray crystallography analysis. The use of the isolated oxidative addition complex in both stoichiometric and catalytic reactions revealed that SO 2 insertion occurs via dissolved SO 2 , likely released upon thermal decomposition of K 2 S 2 O 5 . Key to the success of the reaction is the role of K 2 S 2 O 5 as a reservoir of SO 2 that is slowly released, thus preventing catalyst poisoning.