N-Alkenoylimidazolidin-2-ones as chiral dienophiles in Diels-Alder cycloaddition reactions
Roos, G.H.P., Kriel, K.N., Emslie, N.D. and Balasubramaniam, S. (2000) N-Alkenoylimidazolidin-2-ones as chiral dienophiles in Diels-Alder cycloaddition reactions. South African Journal of Chemistry, 53 (2). pp. 104-112.
Homochiral N-enoylimidazolidin-2-ones 5-8 are readily accessible, practical, and highly diastereoselective dienophiles in dialkylaluminium-promoted Diels-Alder reactions. Acrylate, methacrylate, and (E)-crotonate derivatives bearing ephedrine-based imidazolidin-2-one auxiliaries 1 and 2 undergo rapid, face-selective cycloadditions under mild conditions. High yields of diastereomerically homogeneous products 11-14 are readily obtained by crystallisation or chromatography. The reactivity scope of these systems is extended to less reactive dienes through auxiliary tuning by the application of alternative asparagine-based imidazolidin-2-one auxiliaries 3 and 4.
|Publication Type:||Journal Article|
|Publisher:||South African Bureau for Scientific Publications|
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