Bench-Stable Boryl Dication Enables Aziridinyl Boronate Synthesis via Metal-Free Late-Stage Aziridination with Diverse Nitrogen Nucleophiles

Organoboron compounds are indispensable in modern organic synthesis and biomedical research. This study describes the first synthesis of bench-stable boryl dicationic compound via chemical or electrochemical thianthrenation of vinyl MIDA boronate. Notably, the MIDA boryl group plays a crucial role in thianthrenation, suppressing undesired deborylation and promoting exclusive mono-adduct formation via a formal [4+2] cycloaddition pathway. This unique boryl dication enables a transition-metal-free, chemo- and diastereoselective synthesis of aziridinyl boronates, utilizing a broad range of nitrogen nucleophiles. The method demonstrates remarkable generality, practicality, and functional group tolerance, as evidenced by its application to diverse substrates, including the late-stage modification of several drug molecules. The strategic significance of this approach is further highlighted through electrochemical one-pot protocol and multiple downstream transformations of aziridinyl boronates, offering new opportunities for synthetically challenging boron-containing drug-like scaffolds.