Synlett 2002(3): 0403-0406
DOI: 10.1055/s-2002-20451
LETTER
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Construction of the Azaspiro[5.6]dodec-9-ene System in Marine Natural Toxins

Jun Ishihara, Mariko Horie, Yoshikatsu Shimada, Shingo Tojo, Akio Murai*
Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan
Fax: +81(11)7062714; e-Mail: amurai@sci.hokudai.ac.jp;
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Publikationsverlauf

Received 29 December 2001
Publikationsdatum:
05. Februar 2007 (online)

Abstract

The asymmetric formation of azaspiro[5.6]dodec-9-ene system is described. The Diels-Alder reactions of an α-methylene caprolactam and diene in the presence of a Cu(II) and (S,S)-tBu-BOX complex afford the desired spirocyclic compounds with good exo-selectivity as well as excellent enantioselectivity. These exo-adducts would be applicable to the synthesis of marine natural toxins including the corresponding cyclic imine moiety.