Flash Communication: Dual Geminal <i>sp</i> ³ C–H Activation of a TREN ^TMS Ce-benzyl Complex and Dearylation of the Ylide

sp2 C–H activation of H2C═PPh3 are widely known when H2C═PPh3 is treated with lanthanide alkyls. In this work, an unprecedented reaction mode, in which dual geminal sp3 C–H activation of the TRENTMS ligand and dearylation of the ylide, was reported, generating complex 3. Quantum chemical calculations elucidate the electronic structure of 3, revealing a weakly binding diylide fragment. Our findings highlight that the “straightforward” alkane elimination process is far more complicated than conventionally anticipated.