Struktur und Reaktivität von Bis(π‐pentamethylcyclopentadienyl)‐(2‐methyliden)titanacyclobutan

Structure and Reactivity of Bis(π‐pentamethylcyclopentadienyl)(2‐methylidene)titanacyclobutane The reaction of vinyllithium with bis(π‐pentamethylcyclopentadienyl)titanium dichloride in a molar ratio of 2:1 quantitatively yields the unexpected titanacyclobutane derivative ( 2 ) (Cp* = [C 5 (CH 3 ) 5 ]). The isolated complex 2 has been characterized by spectroscopic methods and by elemental analysis, and its structure has been confirmed by an X‐ray structure determination. The chemical reactivity of 2 is characterized by the splitting of the four‐membered ring at higher temperatures, forming a titanocene vinylidene fragment {Cp 2 *Ti = C = CH 2 } and ethylene. This cycloreversion is confirmed by the fragmentation behavior in the mass spectrometer, and some aspects of it have been studied by Extended Hückel Model calculations.