Composition of the activated complex in the stereoselective deprotonation of cyclohexene oxide by a chiral lithium amide
Chiral lithium amides are being developed for stereoselective synthesis of chiral allylic alcohols in high yields and with high enantiomeric excess. However, rational design of the amides for improved stereoselectivity by computational methods, for example, has not been possible due to lack of knowl...
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| Published in | Tetrahedron: asymmetry Vol. 10; no. 20; pp. 3991 - 3998 |
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| Main Authors | , |
| Format | Journal Article |
| Language | English |
| Published |
Elsevier Ltd
15.10.1999
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| Online Access | Get full text |
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| Summary: | Chiral lithium amides are being developed for stereoselective synthesis of chiral allylic alcohols in high yields and with high enantiomeric excess. However, rational design of the amides for improved stereoselectivity by computational methods, for example, has not been possible due to lack of knowledge of the activated complexes involved in the reactions. Kinetic results are presented for the stereoselective deprotonation by lithium (
S)-1-(2-pyrrolidinylmethyl)pyrrolidide (
1-Li) of cyclohexene oxide
2, in diethyl ether (DEE), to form (
S)-2-cyclohexen-1-ol (
S)-
3 in high enantiomeric excess. The results show that the rate limiting activated complex is composed of one lithium amide monomer and one molecule of
2 and presumably a solvent molecule. The diamine
1 is found to catalyze the deprotonation. |
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| ISSN: | 0957-4166 1362-511X |
| DOI: | 10.1016/S0957-4166(99)00405-X |