Copper-Catalyzed Enantioselective Synthesis of Spirohydroindoles by Ethoxyformylmethylene Oxindole and Iminoester 1,3-Dipole Cycloaddition: An Examination of Associated Biological Activities

A highly enantioselective 1,3-dipolar cycloaddition of ethoxyformylmethylene oxindole with iminoesters has been achieved using the Cu(I)-(S,Sp)-Ph Phosferrox catalytic system, generating a series of chiral spiro[pyrrolidin-3,3'-oxindole] compounds with four consecutive stereocenters, including a spirocycle quaternary center (71%-99% yield, up to >20:1 dr and 95:5 er). The compounds exhibited good inhibitory activity against Valsa mali (V.m.), Fusarium oxysporium (F.o.), and Alternaria brassicae (A.b.).