Synthesis and Characterisation of New Iridium Complexes with the (4S)-2-[2-(Diphenylphosphanyl)phenyl]-4-isopropyl-1,3-oxazoline Ligand That Catalyse Asymmetric Michael Reactions

✍ Scribed by Daniel Carmona; Joaquina Ferrer; Mónica Lorenzo; Fernando J. Lahoz; Isabel T. Dobrinovitch; Luis A. Oro

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 153 KB
• Volume: 2005
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/ejic.200400929

✦ Synopsis

Abstract

The chiral iridium compounds [IrCl(COE){(S)‐PN}] {COE = cyclooctene, PN = (4__S__)‐2‐[2‐(diphenylphosphanyl)phenyl]‐4‐isopropyl‐1,3‐oxazoline, (1)}, [Ir(acac)ClH{(S)‐PN}] {Hacac = acetylacetone, (2)} and [Ir{(S)‐PN}~2~]A {A = Cl (3a,b); BF~4~ (4a,b); PF~6~ (5a,b)} have been prepared, characterised and employed as catalysts for the asymmetric Michael addition of keto or cyano esters to α,β‐unsaturated carbonyl compounds. The X‐ray molecular structures of compounds 2 and 5b are reported. The model catalytic intermediates [IrH(NCCHCO~2~R){(S)‐PN}~2~]Cl {R = Me (12), Et (13)} have also been isolated and characterised. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)