Hydroboration of Nitriles, Esters, and Carbonates Catalyzed by Simple Earth-Abundant Metal Triflate Salts

During the past decade earth-abundant metals have become increasingly important in homogeneous catalysis. One of the reactions in which earth-abundant metals have found important applications is the hydroboration of unsaturated C-C and C-X bonds (X=O or N). Within these set of transformations, the hydroboration of challenging substrates such as nitriles, carbonates and esters still remain difficult and often relies on elaborate ligand designs and highly reactive catalysts (e. g., metal alkyls/hydrides). Here we report an effective methodology for the hydroboration of challenging C equivalent to N and C=O bonds that is simple and applicable to a wide set of substrates. The methodology is based on using a manganese(II) triflate salt that, in combination with commercially available potassium tert-butoxide and pinacolborane, catalyzes the hydroboration of nitriles, carbonates, and esters at room temperature and with near quantitative yields in less than three hours. Additional studies demonstrated that other earth-abundant metal triflate salts can facilitate this reaction as well, which is further discussed in this report.

Automated summary

Earth-abundant metals have become increasingly important in homogeneous catalysis, particularly in the hydroboration reactions of challenging substrates like nitriles, carbonates, and esters. The use of manganese(II) triflate salt in combination with potassium tert-butoxide and pinacolborane enables efficient hydroboration of these substrates with near quantitative yields in less than three hours at room temperature, showcasing a simple and effective methodology for these transformations. Further studies indicate that other earth-abundant metal triflate salts can also facilitate this reaction, expanding the scope of this catalytic process.