Highly enantioselective hydrogenation of enamides catalyzed by chiral phosphoric acids.
نویسندگان
چکیده
A highly enantioselective hydrogenation of enamides catalyzed by a dual chiral-achiral acid system was developed. By employing a substoichiometric amount of a chiral phosphoric acid and acetic acid, catalyst loadings as low as 1 mol % of the chiral catalyst were sufficient to provide excellent yield and enantioselectivity of the reduction product.
منابع مشابه
Asymmetric Rh-Catalyzed Hydrogenation of Enamides with a Chiral 1,4-Bisphosphine Bearing Diphenylphosphino Groups
Much effort has been devoted to the development of efficient asymmetric synthetic methods for the preparation of enantiomerically enriched compounds.1,2 Among various methods for the enantiomerically selective synthesis of chiral organic compounds from prochiral precursors, enantioselective catalytic hydrogenation of dehydro precursors has been extensively developed.3 In fact, asymmetric hydrog...
متن کاملMonodentate chiral spiro phosphoramidites: efficient ligands for rhodium-catalyzed enantioselective hydrogenation of enamides.
Optically active -arylalkylamines are an important class of compounds that are widely used in organic and pharmaceutical synthesis, and much effort has been made to develop efficient asymmetric synthetic methods for them.[1] Asymmetric catalytic hydrogenation of enamides, initiated by Kagan et al. ,[2] provides a direct and convenient route to chiral amine derivatives. However, many well-known ...
متن کاملAsymmetric synthesis of tetrahydro-β-carbolines via chiral phosphoric acid catalyzed transfer hydrogenation reaction.
Chiral phosphoric acid catalyzed enantioselective transfer hydrogenation of hydroxylactams has been realized to provide enantioenriched tetrahydro-β-carbolines in dioxane at room temperature (up to 94% yield, 90% ee).
متن کاملSynthesis of Chiral Fluorinated Propargylamines via Chemoselective Biomimetic Hydrogenation.
A highly enantioselective synthesis of chiral fluorinated propargylamines was developed through phosphoric acid and ruthenium-catalyzed chemoselective biomimetic hydrogenation of the carbon-nitrogen double bond of fluorinated alkynyl ketimines in the presence of a carbon-carbon triple bond. This reaction features high chemoselectivity and slow background reaction. In addition, selective transfo...
متن کاملApplication of phosphine-phosphite ligands in the iridium catalyzed enantioselective hydrogenation of 2-methylquinoline.
The hydrogenation of 2-methylquinoline with Ir catalysts based on chiral phosphine-phosphites has been investigated. It has been observed that the reaction is very sensitive to the nature of the ligand. Optimization of the catalyst, allowed by the highly modular structure of these phosphine-phosphites, has improved the enantioselectivity of the reaction up to 73% ee. The influence of additives ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Organic letters
دوره 11 5 شماره
صفحات -
تاریخ انتشار 2009