- Asymmetric Hydrogenation of Aryl Perfluoroalkyl Ketones Catalyzed by Rhodium(III) Monohydride Complexes Bearing Josiphos Ligands
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The asymmetric hydrogenation of 2,2,2-trifluoroacetophenones and aryl perfluoroalkyl ketones was developed using a unique, well-defined chloride-bridged dinuclear rhodium(III) complex bearing Josiphos-type diphosphine ligands. These complexes were prepared from [RhCl(cod)]2, Josiphos ligands, and hydrochloric acid. As catalyst precursors, they allow for the efficient and enantioselective synthesis (up to 99 % ee) of chiral secondary alcohols with perfluoroalkyl groups. This system does not require an activating base for the hydrogenation of 2,2,2-trifluoroacetophenones. Additionally, the enantioselective C=O hydrogenations of 2-phenyl-3-(haloacetyl)-indoles, a class of privileged structures in medicinal chemistry, is reported for the first time.
- Brüning, Fabian,Nagae, Haruki,K?ch, Daniel,Mashima, Kazushi,Togni, Antonio
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- 3-Substituted 2-phenyl-indoles: Privileged structures for medicinal chemistry
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Privileged structures have been used in drug discovery targeting G protein-coupled receptors (GPCR) and other protein classes for more than 20 years. Their rich activity profiles and drug-like characteristics lend themselves to increased productivity in hit identification and lead optimisation. Recently we discovered two allosteric modulators 1 and 2 for the G protein-coupled receptor GPRC6A incorporating the privileged 2-phenyl-indole scaffold, functionalised at the 3-position. In order to develop new potential GPRC6A ligands we engaged in the development of synthetic routes to provide 2-phenyl-indoles with a variety of substituents at the indole 3-position. Herein we describe the development of optimised and efficient synthetic routes to a series of new 2-phenyl-indole building blocks 3 to 9 and show that these can be used to generate a broad variety of 3-substituted 2-phenyl-indoles of interest to medicinal chemists.
- Johansson, Henrik,Jorgensen, Tanja Bogeloov,Gloriam, David E.,Braeuner-Osborne, Hans,Pedersen, Daniel Sejer
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p. 945 - 960
(2013/04/24)
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