Etudes sur le mecanisme de la metathese des olefines : III. Intermediaires tungstacyclopentaniques et tungstacyclobutaniques

With a view to understanding the role of the catalyst in olefin metathesis various attempts were made to synthesize possible intermediates of the reaction. No compound was formed which could account satisfactorily for a metathesis reaction under conditions favourable for the formation of tungstacyclopentane. Attempted synthesis of tungstacyclobutane also failed, but gave results which could be interpreted as mimicking metathesis. In spite of this apparent agreement, it is concluded that, if tungstacyclobutanes are actually formed, they are decomposed to tungstacarbene (alkylidenetungsten) and olefins rather than to tungstacyclopentanes, then to olefins.