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 in | Tetrahedron: asymmetry Vol. 8; no. 22; pp. 3755 - 3764 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
OXFORD
Elsevier Ltd
27.11.1997
Elsevier |
Subjects | |
Online Access | Get full text |
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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 |
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ISSN: | 0957-4166 1362-511X |
DOI: | 10.1016/S0957-4166(97)00499-0 |