Titanocene methylidene
= Titanocene methylidene
The reactive early-metal alkylidene $\mathrm{Cp_2Ti{=}CH_2}$. <carbonyl> methylenation proceeds through an <oxatitanacyclobutane>; <alkene> capture gives a <titanacyclobutane>. Its <oxygen> affinity makes <ester> methylenation feasible.