A Comment on the Gurjar Mechanism for Alkene Isomerization Using the Grubbs Olefin Metathesis Catalysts

Abstract

The mechanism of allylic alcohol isomerization in the presence of the Grubbs metathesis catalysts is discussed.

Key words

Grubbs - atom transfer - isomerization - mechanism - ­allylic alcohol - metathesis

References

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  Whilst metallacyclobutanes are universally accepted as intermediates [9] (or possibly transition states [10] ) in metathesis reactions their isolation in the case of Ru is hampered by their lability. [11]

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  We have yet to rule out the possibility that this ‘isomerization’ reaction might proceed via an elimination-intermolecular Kharasch sequence. Experiments are in hand to differentiate between these alternate pathways.

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  in this study Grubbs reported the 1,2-addition of hydride (rather than conjugate reduction) to an α,β-unsaturated ketone when treated to propan-2-ol, H₂ and NaOH in the presence of post-metathesis catalyst.

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