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Article info. : 2005; 2(4) (pp 244~337)
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Enantioselective Conjugate Addition to
a,b-Unsaturated Esters and Amides Mediated by Lithium Perchlorate
M.R. Saidia,*,1, R.S. Browna,*
and F. Rajabib
aDepartment of Chemistry, Queen�s University,
Kingston, Ontario, Canada
bDepartment of Chemistry, Department of Chemistry,
Sharif University of Techology,
P. O. Box 11365- 9516 Tehran, Iran
(Received 10 September 2005, Accepted 25 September 2005)
An efficient method for the enantioselective 1,4-conjugate
addition of amines to a,b-unsaturated
esters containing an inexpensive chiral auxiliary, such as (S)-2-methyl-1-butanol
and fenchyl alcohol, in solvent-free conditions mediated by solid lithium
perchlorate is reported. Over 12 examples of the products are generated in
excellent yields, accompanied by moderate enantioselectivity. The concentrated
solution of LiClO4 in a diethyl ether system works well for the
enantioselective 1,4-addition of organolithium compounds to a,b-unsaturated amides
without any side reactions.
Keywords:
Enantioselective, Conjugate addition,
Chiral auxiliary, Solvent-free, Unsaturated esters, Lithium
perchlorate
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