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Iridium‐Catalyzed Hydrogenation of β‐Dehydroamino Acid Derivatives Using Monodentate Phosphoramidites
Author(s) -
Enthaler Stephan,
Erre Giulia,
Junge Kathrin,
Schröder Kristin,
Addis Daniele,
Michalik Dirk,
Hapke Marko,
Redkin Dmitry,
Beller Matthias
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.200800241
Subject(s) - chemistry , iridium , denticity , asymmetric hydrogenation , catalysis , enantioselective synthesis , catalytic hydrogenation , combinatorial chemistry , organic chemistry , medicinal chemistry , crystal structure
The iridium‐catalyzed asymmetric hydrogenation of 13 different β‐dehydroamino acid derivatives to give optically active β‐amino acid esters has been examined. Readily accessible monodentate octahydrobinaphthol‐based phosphoramidites were used as chiral ligands. Good to excellent enantioselectivities and yields were obtained for the E isomers, whereas poorer catalyst performance was found for the Z isomers. Importantly, to obtain high enantioselectivity, substitution at the 3,3′‐positions of the ligands was necessary. Enantioselectivities of up to 94 % ee were achieved under optimized conditions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)