An Electrochemical Strategy for Chalcogenation of closo-Dodecaborate (B₁₂H₁₂)^2- Anion

Advancements in thermal neutron generation technologies within clinical environments have led to a renewed interest in developing boron-containing compounds for boron neutron capture therapy (BNCT). Previous syntheses of several key boron cluster-based therapeutics with clinical relevance are low-yielding and have complicated workup procedures. Using electrolytic methods, we report the in situ oxidation of pseudohalides, [SCN]^- and [SeCN]^-, to synthesize pseudohalogenated products, B₁₂H₁₁YCN^2- (Y = S or Se). Further, these compounds can be reduced to their respective thiol or selenol, [B₁₂H₁₁SH]^2- (BSH) or [B₁₂H₁₁SeH]^2- (BSeH), which are exceedingly nucleophilic and able to form zwitterionic sulfonium and selenonium compounds using alkyl-based electrophiles. The newly reported preparation of BSH and BSeH provides an efficient and convenient route to the preparation of key chalcogenated boron cluster building blocks for the biomedical and materials science communities.