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Enantioselective CpRu‐Catalyzed Carroll Rearrangement – Ligand and Metal Source Importance
Author(s) -
Linder David,
Buron Frédéric,
Constant Samuel,
Lacour Jérôme
Publication year - 2008
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200800854
Subject(s) - chemistry , enantiopure drug , enantioselective synthesis , stereocenter , regioselectivity , nucleophile , catalysis , ligand (biochemistry) , pyridine , medicinal chemistry , naphthalene , combinatorial chemistry , organic chemistry , biochemistry , receptor
Abstract The addition of unstabilized carbonyl nucleophiles to unsymmetrical allyl‐metal fragments still represents a challenge to generate stereogenic centers enantio‐ and regioselectively. In this context, the decarboxylative Carroll rearrangement of allyl β‐keto esters is particularly interesting, since chiral γ,δ‐unsaturated ketones are obtained. Herein, we show that CpRu half‐sandwich complexes can, with selected enantiopure pyridine‐monooxazoline ligands, catalyze this transformation and afford complete conversions along with good levels of regioselectivity and enantioselectivity. Even more challenging (electron‐poor) substrates react (up to 86 % ee , branched/linear ratio ≥ 97:03). In addition, the use of an air‐stable metal precursor, namely [CpRu(η 6 ‐naphthalene)][PF 6 ], allows the reaction to be carried out reproducibly evenin non‐anhydrous THF with a catalyst loading as low as2 mol‐%. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)