Amino-Indanol-Catalyzed Asymmetric Michael Additions of Oxindoles to Protected 2-Amino-1-nitroethenes for the Synthesis of 3,3′-Disubstituted Oxindoles Bearing α,β-Diamino Functionality
An organocatalytic asymmetricMichaeladdition reaction of 3-substituted oxindoles to protected 2-amino-1-nitroethenes has been developed. The reaction is catalyzed by a simple and readily available amino-indanol derivative and affords the desired products in very high yields (up to 99%) with excellent diastereoselectivities (up to >99:1) and very good enantioselectivities (up to 90%). Significantly