M.-K. Zhu et al. / Tetrahedron: Asymmetry 17 (2006) 491–493
30 mol% 2
493
O
X
15 mol% (+)-Camphor
Cl
O
Cl
sulfonic acid
+
NO2
Toluene, 0 oC
5 days
NO2
9d
8b, X = O
8c, X = S
X
11a, X = O, 82% yield, dr = 99:1, 81% ee
11b, X = S, 99% yield, dr = 99:1, 81% ee
Figure 2. Michael addition of ketones to 9d.
Two cycloketones 8b and 8c were reacted with 9d in the
presence of 30 mol % organocatalyst 2 to give the corre-
sponding products 11a and 11b in 82% and 99% yields
with perfect diastereoselection of 99:1 and good enantio-
selectivities (81% ee) (Fig. 2).
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In conclusion, we have designed and prepared a chiral
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Acknowledgements
We are grateful for financial support from NSFC
(Grants 20472082, 203900505, and 20325211).
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