AbstractWe examine by the means of computational chemistry the ability of two phosphasilenes to transfer the phosphinidene moiety to four double bonded organic functional groups (>C=C<, ‐N=N‐, >C=O, and >C=S) in the presence of different bulky ligands. We show that large bulky groups in the reactants can sterically prohibit the otherwise favored association of reactants and phosphasilenes and instead a new phosphinidene transfer reaction can occur. We find that the transfer reaction mechanism is generally present independent from the functional group and by introducing large enough trimethylsilyl or tert‐butyl‐dimethylsilyl ligands it can be used to transfer phosphinidene to organic functional groups such as thioformaldehydes or diazenes, respectively. We propose that by exploiting the complex bonding nature of low‐valent main group complexes they can act as synthetic equivalents of hitherto unknown very reactive synthons. We encourage experimentalists to explore the reactivity of their main‐group complexes by varying the size of the bulky substituents on the reactants that can result in new unexpected chemistry.