A selective route to aryl-triphosphiranes and their titanocene-induced fragmentation† †Electronic supplementary information (ESI) available: Synthesis and characterization of compounds, NMR spectra, crystallographic, EPR and computational details. CCDC 1915056–1915060. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c9sc02322d

Using titanocene synthon [Cp2Ti(Me3SiC2SiMe3)] the selective conversion of aryl-substituted triphosphiranes P3Ar3 into Cp2TiP2Ar2 complexes was achieved.
Triphosphiranes are three-membered phosphorus cycles and their fundamental reactivity has been studied in recent decades. We recently developed a high-yielding, selective synthesis for various aryl-substituted triphosphiranes. Variation of the reaction conditions in combination with theoretical studies helped to rationalize the formation of these homoleptic phosphorus ring systems and highly reactive intermediates could be isolated. In addition we showed that a titanocene synthon [Cp2Ti(btmsa)] facilitates the selective conversion of these triphosphiranes into titanocene diphosphene complexes. This unexpected reactivity mode was further studied theoretically and experimental evidence is presented for the proposed reaction mechanism.