2002 Catalysis

CatalysisO 0020 Iridium-Catalyzed Allylic Substitution: Stereochemical Aspects and Isolation of

IrIII Complexes Related to the Catalytic Cycle. — The allylic substitution reaction of allylic acetates catalyzed by iridium complexes is studied concerning the influence of various reaction parameters, subtitution pattern and configuration of starting mate-rials and the nature of ligands on the stereoselectivity of the substitution reaction. Best results are obtained using phosphite-derived ligands and LiCl as additive. The allylic alkylation reaction of enantiopure allylic acetate (I) proceeds with partial retention of the initial configuration (up to 87% retention). Alkylation of various racemic allylic ac-etates (I) and (V) in the presence of a chiral binaphthol-derived phosphorus amidite pro-vides the products in up to 86% optical purity. The catalytically active species are stud-ied in detail. A first application of the described catalytic system to the allylic amination of acetate (I) proceeds with low enantioselectivity. — (BARTELS, B.; GARCIA-YEBRA, C.; ROMINGER, F.; HELMCHEN*, G.; Eur. J. Inorg. Chem. 2002, 10, 2569-2586; Org.-Chem. Inst., Ruprecht-Karls-Univ., D-69120 Heidelberg, Germany; Eng.) — Mischke

04- 027

2002 Catalysis