Organocatalytic asymmetric 3+3 annulation of isatin N,N’-cyclic azomethine imines with enals:Efficient approach to functionalized spiro N-heterocyclic oxindoles

摘要

An unprecedented chiral secondary amine-catalyzed [3+3] annulation of isatin N,N’-cyclic azomethine imines with α,β-unsaturated aldehydes was developed.This strategy allowed the construction of structurally novel spiro N-heterocyclic oxindole derivatives in good yields(up to 91%) and good to excellent enantioselectivities(up to>99% ee),albeit with modest diastereoselectivities(up to 3.1:1 dr).