An easy entry to optically active spiroindolinones: Chiral Brønsted acid-catalysed Pictet-Spengler reactions of isatins

Abstract

The first catalytic asymmetric Pictet-Spengler reaction of isatins is presented. BINOL-derived phosphoric acids were found to be competent catalysts for this transformation, giving challenging spirooxindole structures bearing a quaternary stereocentre with generally good results. The 1,2,3,4-tetrahydro- β-carboline products (spiroindolinones) are the core of some newly discovered anti-malarial agents. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.