Bisphosphane‐Stabilized Borylenes: Unlocking Borylene Transfer Reactivities

ABSTRACT The development of borylene‐transfer reactions—a powerful yet underdeveloped strategy for the efficient construction of boron‐containing compounds—has been hindered by the scarcity of reliable reagents. A fundamental challenge lies in balancing the high ambiphilic reactivity required for transfer with the requisite molecular stability. Herein, we report the synthesis of a series of bisphosphane‐stabilized borylenes and disclose their exceptional borylene‐transfer capabilities. The target borylenes ( 3 ) were prepared via facile deprotonation of the corresponding bisphosphane‐coordinated hydroboronium precursors using KHMDS (potassium bis(trimethylsilyl)amide). Notably, borylene 3a undergoes formal B─H bond insertion with hydroboranes to yield diborane (6) derivatives. Furthermore, 3a facilitates unprecedented borylene transfer to polar π systems, including benzaldehyde and chalcone, providing efficient access to three‐membered oxaboriranes and boriranes. Experimental and computational studies reveal that the labile phosphorus–boron (P–B) coordination is pivotal in maintaining the high borylene‐transfer capability of 3a . These preliminary results set the stage for the use of stable hydroboronium compounds as practical borylene‐transfer reagent precursors in synthetic chemistry.