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Scheme 6. Reagents and conditions: a: LiAlH4, THF, reflux;
b: NaIO4, MeOH, H2O, rt; c: NaClO2, KH2PO4, 2-methyl-2-
butene, t-BuOH, H2O, rt; d: (i) Ac2O, DMAP, pyridine, rt,
(ii) 3-methyl-1-p-tolyltriazene, EtOAc, rt, 29% 24 from 9.
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Acknowledgements
Financial support of this work by the Deutsche
Forschungsgemeinschaft and the Fonds der Chemis-
chen Industrie is gratefully acknowledged. J.Z. thanks
the China Scholarship Council for a research stipend.
13. Crystallographic data (excluding structure factors) for the
structures in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplemen-
tary publication numbers CCDC 214333 (ent-9) and
CCDC 214334 (11). Copies of the data can be obtained,
free of charge, on application to CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (Fax: +44(0)-1223-336033 or
e-mail: deposit@ccdc.cam.ac.uk).
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