Selective Scrambling of Phenyl‐Stannanes: Main Group Catalysis With Aromatic Phosphorus Heterocycles

We report the first example of metal‐free catalysis using aromatic phosphorus heterocycles that mediates a mutual hydride–phenyl substituent transfer between two tin centers, enabling controlled substituent redistribution. This unique reactivity allows phenylstannanes bearing different numbers of phenyl groups to be selectively and completely converted into the same products, SnPh 4 , H 2 , and elemental Sn, via transient SnH 4 . Comprehensive experimental and computational studies reveal three interconnected catalytic cycles involving reversible hydride and phenyl transfer steps, all initiated by the intrinsically weak P→B interaction in the phosphinine‐borane adduct. Within this species, both components play distinct roles in balancing the energetics of the reaction network: the borane functions as a hydride abstractor, whereas the phosphinine facilitates the stannyl transfer step. Our findings establish a new paradigm in main‐group catalysis enabled by low‐coordinate phosphorus species and the highly labile adducts they form.