Highly Enantioselective Synthesis of Multifunctionalized Dihydrofurans by Copper-Catalyzed Asymmetric [4+1] Cycloadditions of α-Benzylidene-β-ketoester with Diazo Compound

Highly efficient synthesis of chiral tetrasubstituted 2,3-dihydrofuran derivatives has been realized by Cu-catalyzed asymmetric [4 + 1] cycloadditions of alpha-benzylidene-beta-ketoester with a diazo compound. Following this methodology, a series of optically active multifunctionalized dihydrofurans were prepared in high yield with up to 96% ee and 99/1 dr.