The photolysis of W(CO)6in CH2Cl2 produces (CO)5WCH2Cl2. The high reactivity of (CO)5WCH2Cl2 (1) was exploited to synthesize a vinylidene complexes via the acetylene-vinylidene rearrangement. The addition of a terminal acetylene (H-C≡C-COOCH3) to a solution of (1) produced the η2-acetylene-pentacarbonyltungsten complex (CO)5W(η2-HC≡C-COOCH3) in good yield. The production of the vinylidene complex (CO)5W=C=CH-COOCH3in equilibrium with the acetylene complex in the reaction medium was verified experimentally by reaction with excess imine. The heterocyclic organometallic compound of tungsten obtained was separated and purified and its structure was studied by IR, 1H NMR, 13C NMR and mass spectrometry in comparison with the thermal analysis and elemental analysis data. The final aim of this investigation is the development of a new alternative route to a β-lactame with antibacterial activity.