A highly enantioselective α-amination of 3-substituted oxindoles with azodicarboxylates catalyzed by a chiral Sc(OTf)3/N,N′-dioxide complex (Tf: triflate) has been developed and affords the corresponding 3-amino-2-oxindole derivatives in high yields (up to 98 %) with excellent enantioselectivities (up to 99 % ee). The procedure is capable of tolerating a relatively wide range of substrates, and excellent results (92–96 % ee) can also be obtained, even in the presence of 0.5 mol % of catalyst loading under mild conditions. These results showed the potential value of the catalytic approach. Moreover, with high synthetic versatility, the product could be easily transformed into optically active 3-amino-3-methyloxindole bearing a chiral quaternary stereogenic center.
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