Synfacts 2006(7): 0656-0656  
DOI: 10.1055/s-2006-941838
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Synthesis of Δ 2-Isoxazolines

Contributor(s): Victor Snieckus, Bärbel Wittel
C. K. Y. Lee, A. J. Herlt, G. W. Simpson, A. C. Willis, C. J. Easton*
Australian National University, Canberra, Australia
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Publikationsverlauf

Publikationsdatum:
22. Juni 2006 (online)

Significance

The synthesis of di- and trisubstituted Δ2-isoxazolines from isoxazoles by reduction or conjugate addition reactions is reported. In the former method, an excess of sodium borohydride is required and leads predominantly to trans-isoxazolines, the exception being for the reaction of R2 = CH2OH substituted isoxazoles for which the cis-isomer was obtained as the major product (20:70, cis:trans). Using the Luche methodology (Tetrahedron Lett. 1988, 29, 5373-5374), the highly stereoselective and high-yielding conjugate addition using a combination of zinc dust, cuprous iodine and an alkyl iodide leads exclusively to C5-alkylated trans-isoxazolines.