Metal Alkoxide Promoted Regio‐ and Stereoselective CO and CC Metathesis of Allenoates with Aldehydes

The reaction of 2,3-allenoates and aldehydes in the presence of an alkoxide affords alkyl 4,5-diaryl-3-oxo-2-propylpent-4(E)-enoates and cis-3,4-diaryloxetanes through a formal C=O and C=C metathesis. A mechanism for this reaction has been proposed.