Stereoselective Aldol Addition to Rhenium(I) Complexes and Reversible Dimerization with Epimerization of the Metal Center
Herein, we report several examples of stereoselective aldol additions of aldehydes or ketones to ReI tricarbonyl complexes to form monomeric derivatives in good yields. The metal‐centered chirality defines the final stereochemistry of the carbon atom of the monomeric ReI complex after the addition. However, it cannot control the resulting stereochemistry of the enolate part, and thus, if the α‐carbon atom of the reagent is prochiral, a mixture of diastereoisomers is obtained. On the other hand, all of the monomeric complexes can be reversibly dimerized in basic media to form cis dimers, for which an epimerization of the metal‐centered chirality is required in order to avoid steric congestion. All of these results are supported by exhaustive crystallographic analysis.
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | artículo biblioteca |
| Published: |
Wiley-VCH
2013-06-17
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| Subjects: | Metal Complexes, Rhenium, Dimerization, Aldol reaction, Chiroptical Compounds, |
| Online Access: | http://hdl.handle.net/10261/178826 http://dx.doi.org/10.13039/501100004837 http://dx.doi.org/10.13039/501100014180 |
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| Summary: | Herein, we report several examples of stereoselective aldol additions of aldehydes or ketones to ReI tricarbonyl complexes to form monomeric derivatives in good yields. The metal‐centered chirality defines the final stereochemistry of the carbon atom of the monomeric ReI complex after the addition. However, it cannot control the resulting stereochemistry of the enolate part, and thus, if the α‐carbon atom of the reagent is prochiral, a mixture of diastereoisomers is obtained. On the other hand, all of the monomeric complexes can be reversibly dimerized in basic media to form cis dimers, for which an epimerization of the metal‐centered chirality is required in order to avoid steric congestion. All of these results are supported by exhaustive crystallographic analysis. |
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