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.).