Iridium-catalyzed cascade decarbonylation/highly enantioselective Pauson-Khand-type cyclization reactions

摘要

An easily accessible chiral iridium-BINAP complex can effect the cooperative processes of decarbonylation of an aldehyde and cascaded enantioselective Pauson-Khand-type reaction. A survey of ligands revealed that atropisomeric aryl-diphosphine ligands were superior to chiral alkyl-diphosphines in this dual catalysis. Applying the reaction conditions of [IrCl(COD)](2)/(S)-BINAP complex with nonylaldehyde as a CO surrogate at 100 degrees C in anhydrous dioxane solvent, various 1,6-enynes were transformed to the corresponding optically active bicyclic cyclopentenones with excellent enantioselectivities (up to 98% ee). (c) 2006 Elsevier Ltd. All rights reserved.