| Autor: |
Aït-Haddou H; Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. hassan@zyvex.com, Hoarau O, Cramailére D, Pezet F, Daran JC, Balavoine GG |
| Jazyk: |
angličtina |
| Zdroj: |
Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2004 Feb 06; Vol. 10 (3), pp. 699-707. |
| DOI: |
10.1002/chem.200204649 |
| Abstrakt: |
The origin of the reversal of the enantioselectivity in the palladium-catalyzed allylic alkylation of rac-1,3-diphenyl-2-propenyl acetate with dimethyl malonate anion using chiral dihydroxy bis(oxazoline) "BO" ligands derived from (1S,2S)-(+)-2-amino-1-phenyl-1,3-propanediol was investigated. To determine the structural effects of the dihydroxy BO ligand on this unique phenomenon, new homochiral dihydroxy BO ligands were prepared from L-threonine and L-serine and were assessed in the transformation. The results obtained with these novel BO ligands, compared with the one obtained by using the dihydroxy BO ligands derived from (1S,2S)-(+)-2-amino-1-phenyl-1,3-propanediol, reveal that the reversal in the enantioselectivity observed with the dihydroxy BO ligand depends on the structure of the ligand. The effect of different bases used to generate the dimethyl malonate anion was also examined. The results are discussed in terms of the interaction of one hydroxy group in the intermediate pi-allyl palladium complex with the dimethyl malonate anion. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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