ASYMMETRIC SYNTHESIS OF t-BUTYL 3-ALKYL-OXINDOLE-3- CARBOXYLATES VIA CHIRAL PHOSPHORIC ACID-CATALYZED DESYMMETRIZATION OF DI-t-BUTYL 2-ALKYL-2-(2-AMINOPHENYL)MALONATES

摘要

We describe the asymmetric desymmetrization of di-t-butyl 2-alkyl-2-(2-aminophenyl)malonates to prepare enantioenriched t-butyl 3-alkyl-oxindole-3-carboxylates using (S)-TRIP, a chiral phosphoric acid. Optimization study increased the enantioselectivity up to 66% ee.