Enforcing Z-selectivity in olefin metathesis through use of catalysts grafted on well-defined phenolic hybrid material

• New olefin metathesis catalysts were prepared by replacing surface silanol by phenol.
• SOMC of a W-perhydrocarbyl on supported phenol.
• SOMC of Mo-bispyrrolide alkylidene complexes on supported phenol.
• Improvement of the activity of the aryloxide supported Mo and W in propylene metathesis.
• Introducing a phenolic spacer enhances the stereoselectivity towards the Z isomer.

We have developed a new hybrid material, featuring single-site phenolic functions on a silica surface. This new material was used for the grafting, by surface organometallic chemistry, of tungsten perhydrocarbyl and molybdenum bispyrrolide alkylidene complexes. Dramatic improvements in terms of activity and stability were observed in propylene metathesis, when compared to the silica counterpart. Introducing a phenolic spacer between the active molybdenum center and the surface enhances the stereoselectivity towards the Z isomer.

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