Electroreductive Nickel‐Catalyzed Thiolation: Efficient Cross‐Electrophile Coupling for C−S Formation

Abstract

Sulfur‐containing molecules are of utmost topical importance towards the effective development of pharmaceuticals and functional materials. Herein, we present an efficient and mild electrochemical thiolation by cross‐electrophile coupling of alkyl bromides with functionalized bench‐stable thiosulfonates to access alkyl sulfides with excellent efficacy and broad functional group tolerance. Cyclic voltammetry and potentiostatic analysis were performed to elucidate mechanistic insights into this electrocatalytic thiolation reaction.

Recent Metal-Catalyzed Methods for Thioether Synthesis

“…116 Scheme 30 Electro-reductive synthesis of alkyl-aryl and dialkyl thioethers. 113 These reports demonstrate the potential of electrochemistry to contribute to the field of cross-coupling chemistry. Although only nickel has been utilized in the electrochemical C-S bond-forming metal catalysis, future research might also embrace other 3d transition metals such as iron, cobalt or manganese.…”

“…[110][111] Widening the spectrum of thiol-precursors, Ang and Ackermann developed an electroreductive nickel-catalyzed synthesis of alkyl-aryl and dialkyl thioethers (Scheme 30). 113 They were able to employ odorless thiosulfonates 37 in an electrolyte-free crosselectrophile coupling with alkyl bromides 36 using the NiBr2/bipy (L13, 2,2′-bipyridine) catalyst system. A good functional group tolerance was shown, e.g.…”

Carbon‐Sulfur Bond Constructions: From Transition‐Metal Catalysis to Sustainable Catalysis

“…Wang and co-workers [43] Ang and Ackerman [44] developed an efficient electrochemical thiolation protocol for the preparation of alkyl sulfides 133 via cross-electrophile coupling between alkyl bromides and functionalized bench-stable thiosulfonates as shown in Scheme 38. Interestingly, a variety of alkyl bromides underwent CÀ S bond formations with different thiosulfonates possessing diverse functionalities to afford the resulting alkyl sulfides in good to excellent yields.…”

Recent Advances in Nonprecious Metal Catalysis

“…Methodologies have been developed for C–C, ,, C–N, and C–S bond formations that utilize electrochemical oxidation or reduction for catalyst turnover. Ackermann and co-workers published an electrochemical cross electrophile coupling between alkyl bromides and thiosulfonates as an extension of a previous report using a stoichiometric metal reductant (Scheme ). The reaction utilizes 2,2′-bipyridine as a ligand and generates both alkyl and aryl thioethers in good yields (80–90% for most substrates).…”