Chiral nitroalkenes are used for the first time in Michael additions of aldehydes, catalyzed by pyrrolidine derivatives. They yield the same major stereoisomer with either ()-proline or ()-proline, but this asymmetric induction does not overcome the effect of sterically more congested catalysts. Nitrocyclobutane intermediates are often formed, which are more stable than those from ()-1-nitro-2-phenylethene. The cyclobutanes and final products were characterized by 2D NMR and chemical correlations.
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