Organocatalytic Asymmetric Michael Addition of 1-Acetylindolin-3-ones to α,β-Unsaturated Aldehydes: Synthesis of 2-Substituted Indolin-3-ones

A highly efficient asymmetric Michael addition of 1-acetylindolin-3-ones to α,β-unsaturated aldehydes is developed to afford 2-substituted indolin-3-one derivatives in high yields (up to 94%) with good stereoselectivities (up to 11:1 dr and 96% ee). The Michael adducts can be transformed into substituted cyclopentyl[b]indoline compounds conveniently without racemization.