Enantioselective 1,3-Dipolar Cycloaddition Reaction between Diazoacetates and alpha-Substituted Acroleins:Total Synthesis of Manzacidin A

摘要

Diazoalkanes have been widely utilized in 1,3-dipolar Cycloaddition reactions with various olefins to construct synthetically useful pyrazolines and pyrazoles,which are easily derivatized to various types of nitrogen-containing molecules.The asymmetric variants of this transformation were previously effected by a chiral auxiliary-based approach using,for example,camphor sultam-derived dipolarophiles.To the best of our knowledge,only one successful example has been recently reported of chiral Lewis acid-catalyzed enantioselective 1,3-dipolar Cycloaddition of diazoalkanes with 3-(2-alkenoyl)-2-oxazolidinones as a bidentate dipolarophile.