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 α-benzylidene-β-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.