C O M M U N I C A T I O N S
Table 3. Mercuriocyclization of 1 Using 4-Naphthylbisoxazoline
(L*)-Hg(II) Complexes
droxyalkene 20 was cyclized under the identical conditions to
furnish tetrahydropyran 21 in 91% ee and 48% yield along with
41% of recovered 20.
In conclusion, we have developed highly enantioselective mer-
curiocyclization of γ-hydroxy-cis-alkenes employing novel tartrate-
derived 4-(2-naphthyl)bisoxazoline 2n to produce 2-monosubstituted
tetrahydrofurans up to 95% ee.
entry
L*
% yield
% ee
1
2m
2n
2n
74
75
75
74 (R)
90 (R)
95 (R)
Acknowledgment. This work was supported by CMDS, Cre-
ative Research Initiatives of the Korean Ministry of Science and
Technology, and the Brain Korea 21 Project.
2
3a
a 5 equiv of K2CO3 and 10 equiv of MeOH were added.
Supporting Information Available: Experimental details (PDF).
This material is available free of charge via the Internet at http://
pubs.acs.org.
Table 4. Mercuriocyclization Using Bisoxazoline 2n-Hg(II)
Complex (1.2 equiv) in the Presence of K2CO3 (5 equiv) and
MeOH (10 equiv)
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92e,f
89e,f
91 (R)e,g
a Percentage of recovered sm in parentheses. b Due to its volatility, sm
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(entries 2, 3, and 7). Alkyl chain-containing substrates 5 and 6
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Since 2l seemed to be a little better than 2k in terms of
enantioselectivity and stability, 4-naphthylbisoxazolines 2m and
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experimental data in Table 3 manifest that 4-(2-naphthyl)bisoxa-
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