Lewis acid tuned facial stereodivergent HDA reactions using beta-substituted N-vinyloxazolidinones.
The [4 + 2] acido-catalyzed heterocycloaddition between new beta-substituted N-vinyl-1,3-oxazolidin-2-ones (with R' = Me, Ar, CH2 Ar) and beta,gamma-unsaturated alpha-ketoesters (R = Ar) afforded heteroadducts with high levels of endo and facial selectivities. A complete reversal of facial differentiation was achieved by varying the Lewis acid, leading to the stereoselective formation of either endo-alpha or endo-beta adducts. [reaction: see text].
Gohier
Frédéric
F
UMR 6011 CNRS-Université du Maine, Laboratoire de Synthèse Organique (UCO2M), Faculté des sciences, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9, France.
Bouhadjera
Keltoum
K
Faye
Djibril
D
Gaulon
Catherine
C
Maisonneuve
Vincent
V
Dujardin
Gilles
G
Dhal
Robert
R