| Autor: |
Kwunmin Chen, Pang Min Liu, Dhananjay R. Magar |
| Rok vydání: |
2010 |
| Předmět: |
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| Zdroj: |
European Journal of Organic Chemistry. 2010:5705-5713 |
| ISSN: |
1434-193X |
| DOI: |
10.1002/ejoc.201000695 |
| Popis: |
A series of pyrrolidine-camphor-derived organocatalysts (1-4) were designed and synthesised. These organocatalysts were used for direct α-amination of aldehydes with dialkyl azodicarboxylates to give the desired α-aminated products in high chemical yields (up to 92 %) and with high to excellent levels of stereoselectivity (up to >99 % ee). The reactions proceeded rapidly (within 5 min) with low catalyst loading (5 mol-%) at ambient temperature. Enantioselective aminations of asymmetric α,α-disubstituted aldehydes in the catalytic system were studied, with reasonable to high stereo-selectivities (up to 75 % ee) being obtained. The utility of this methodology was demonstrated with the synthesis of derivatives of β-amino-γ-butyrolactone and a tetrasubstituted cyclohexane-derived amino alcohol with high stereoselectivities. Transition models were proposed for the asymmetric α-amination reactions; they involve hydrogen-bond interactions between the nucleophilic enamine formed in situ and the nitrogen source. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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