Desymmetrization of Diboron(4) by a Trifluorination B-Masking Strategy: Practical Synthesis of Unsymmetrical Diboron Species

Herein, we report a straightforward practical and simple method for efficiently synthesizing a BF₃-containing unsymmetrical diboron salt. This method involves the direct desymmetrization of commercially available diboron(4). This desymmetrization is based on a selective B-masking strategy via nucleophilic trifluorination, providing the elusive diborons bearing a trifluoroborate group. The synthetic utility of these salts is demonstrated through various examples of (sequential) B-ligand interconversions, enabling the synthesis of unsymmetrical diboron derivatives. These products, which serve as valuable building blocks, are obtained in gram-scale and high yields.