J. S. Yada6 et al. / Tetrahedron Letters 42 (2001) 6385–6388
6387
Acknowledgements
N-substituted allylic amines from 5-iodomethyl-2-
oxazolidinones.
Two of the authors (A.B./B.V.S.R.) are thankful to
UGC/CSIR, New Delhi, respectively, for financial sup-
port. We are thankful to Dr. N. W. Fadnavis for
HPLC analysis.
Scheme 1 illustrates the synthesis of 5-iodomethyl-2-
oxazolidinones from allylic alcohols via optically active
aminodiols. Allylic alcohols 1 were subjected to Sharp-
less asymmetric epoxidation15 to afford epoxy alcohols
2 which, on selective ring opening with amines,16 gave
optically active aminodiols 3. The aminodiols 3 were
treated with methyl chloroformate and potassium car-
bonate in THF at 0°C for 6–7 h17 to give the bis-car-
bonates 4. The crude carbonates 4 were treated with
10% potassium hydroxide in methanol to afford 5-
hydroxymethyl-2-oxazolidinones 5 in good yield. Treat-
References
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with indium metal in refluxing methanol for 4–6 h gave
the corresponding chiral amines 7 in good yields
(Scheme 2).
Several examples illustrating this novel and practical
method for the synthesis of chiral allylic amines are
listed in Table 1.19 The experimental procedure is very
simple and the products are obtained in high yields.
The reaction proceeds smoothly under mild conditions.
No racemization or decomposition of the products is
observed under the reaction conditions as confirmed by
chiral HPLC.20 Unlike zinc or tin, indium does not
require any acidic promoters or activators or anhy-
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clean and no side products are observed. Methanol
appears to be the choice of solvent for this reaction.
Among various metals such as indium, samarium,
yttrium and tin used for this transformation, indium
was found to be more effective than others in terms of
yields and reaction times. For example, treatment of
3-benzyl-5-iodomethyl-4-phenyl-(4R,5R)-1,3-oxazolan-
2-one (entry 1b) with different metals such as indium,
samarium, yttrium and tin for 5 h gave the correspond-
ing chiral allylic amine (entry 2b) in 92, 71, 52 and 65%
yield, respectively, under typical reaction conditions.
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amines using metallic indium. In addition to its simplic-
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yields of products in short reaction times which makes
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Scheme 2.