An Efficient Route to Highly Enantioenriched Tetrahydroazulenes and β-Tetralones by Desymmetrization Reactions of δ,δ-Diaryldiazoaceto-acetates.

A highly stereoselective desymmetrization reaction of δ,δ-diaryl-α-diazo-β-ketoesters catalyzed by chiral dirhodium carboxylates forms aromatic cycloaddition products in up to 97% ee.