Generation by Electrochemical Routes

It was found that under electrochemical conditions with dichloromethane as solvent and with a sacrificial aluminium anode, a metallacarbene could be directly synthesized from [WClg] or [M0CI5]. 

Strong evidence has been obtained for the participation of the solvent in this reaction, since when using CD2CI2, an initial burst of [D2] propene and [Dj] 1-butene is observed during metathesis of 2-pentene. Subsequently only butenes and hexenes are formed as metathesis products. The initial propene and 1-butene arise from the combination of 2-pentene derived alkylidene moieties with a methylidene group. Carbon-13 NMR spectroscopy also indicate the possible presence of a methylidene group. 

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