Oxygen group functionalised complexe

Once the hydroxy functionalised imidazolium salt is formed, it can be deprotonised and reacted with various metal complexes to form (transition) metal carbene complexes. The hydroxy group ensures that the ligand can be coordinated even to metals that are normally reluctant to form stable carbene complexes. A good example is the deprotonation of a hydroxyethyl functionalised imidazolium salt with potassium hydride [36]. The potassium cation coordinates to the oxygen atom of the alkoxide sidechain and forms cubes as structural elements (see Figure 4.6). The carbene end then coordinates to the respective... 

Closely related to the previous section is the asymmetric addition of allyl stannanes to aldehydes. The catalyst is the same and the main difference is that an R3Sn group is lost instead of a proton. This has the advantage that there is no ambiguity about the position of the alkene in the product. An example is the addition of an allyl group to the functionalised aldehyde 199. Complexation of either or both oxygen atoms to the Ti is indicated.45... 

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