Primary Products and Mechanistic Considerations in Alkane Metathesis

摘要

We reported in 1997 the discovery of a new catalytic reaction:the metathesis of alkanes.Acyclic alkanes,except methane,when contacted with the silica-supported tantalum hydride [(=SiO)_2Ta-H],1,are transformed at moderate temperatures into their lower and higher homologues.For example,ethane is transformed into methane and propane along with traces of butanes.Interestingly,1 is also able to achieve the reverse reaction,that is,the cross-metathesis of methane and propane,giving two ethanes and thereby incorporating methane into higher alkanes.It is also possible to perform the cross-metathesis of ethane and toluene to give xylenes and ethylbenzene.