New homochiral bis(oxazoline) ligands for asymmetric catalysis

Several homochiral bis(oxazolines), with asymmetric centers on the oxazoline rings and on the side chains, were prepared from (1S,2S)-(+)-2-amino-1-phenyl-1,3-propanediol in high yields. Asymmetric cyclopropanation of styrene with ethyl diazoacetate in the presence of 1 mol% of copper( I) triflate a...

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Published inTetrahedron: asymmetry Vol. 8; no. 22; pp. 3755 - 3764
Main Authors Hoarau, O., Aït-Haddou, H., Castro, M., Balavoine, G.G.A.
Format Journal Article
LanguageEnglish
Published OXFORD Elsevier Ltd 27.11.1997
Elsevier
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Summary:Several homochiral bis(oxazolines), with asymmetric centers on the oxazoline rings and on the side chains, were prepared from (1S,2S)-(+)-2-amino-1-phenyl-1,3-propanediol in high yields. Asymmetric cyclopropanation of styrene with ethyl diazoacetate in the presence of 1 mol% of copper( I) triflate and the dibenzoyl bis(oxazoline) 5a. gave ethyl 2-phenylcyclopropanecarboxylate in up to 85% ee. The same ligand 5a, was used in the palladium catalysed enantioselective allylic substitution of the 1,3-diphenyl-2-propenyl acetate to give the desired product in up to 90% ee. New chiral bis-oxazolines were prepared from (1S,2S)-(+)-2-amino-1-phenyl-1,3-propanediol in high yields. With these ligands, palladium catalysed allylic substitution of the 1,3-diphenyl-2-propenyl acetate was obtained in 90% ee
ISSN:0957-4166
1362-511X
DOI:10.1016/S0957-4166(97)00499-0