Lewis acid tuned facial stereodivergent HDA reactions using beta-substituted N-vinyloxazolidinones.

Org Lett

UMR 6011 CNRS-Université du Maine, Laboratoire de Synthèse Organique (UCO2M), Faculté des sciences, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9, France.

Published: January 2007

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].

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http://dx.doi.org/10.1021/ol062626lDOI Listing

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