Intramolecular conjugate addition reactions of amines and carbamates to 2,5-cyclohexadien-1-ones: Stereoselective synthesis of perhydroindoles

Intramolecular conjugate addition reactions of 4,4-disubstituted-2,5-cycloh exadien-1-ones are described within the context of possible approaches to m anzamine A. Amine 4 provided tricycle 6, with improper relative stereochemi stry for use in an approach to manzamine A. Carbamates 25 and 38 gave perhy droindoles 26 and 28b under conditions of thermodynamic control, respective ly, with the proper relative stereochemistry required for manzamine A. Carb amate 25 Rave diastereomeric perhydroindole 27 under conditions of thermody namic control. (C) 1999 Elsevier Science Ltd. AII rights reserved.