Tetrahedron: Asymmetry

Synthesis and reactivity of N-sugar-maleimides: an access to novel highly substituted enantiopure pyrazolines

NB Hamadi, M Msaddek

Index: Hamadi, Naoufel Ben; Msaddek, Moncef Tetrahedron Asymmetry, 2012 , vol. 23, # 24 p. 1689 - 1693

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Citation Number: 6

Abstract

Two diastereomeric isoxazolines were synthesized in a stereoselective manner with 6.64– 20.36% diastereoisomeric excess. The cycloaddition of N-sugar-maleimide in the presence of MgBr2 afforded isoxazolines with high diasterioselectivities (76–84% de). The 1, 3-dipolar cycloaddition reaction was diastereospecific and enantiomerically pure (3R, 4S, 5S, 6S, 3aR, 6aS)-pyrazolines were obtained from N-sugar-maleimides via 1, 3-proton migration.