Novel monodentate spiro phosphorus ligands for rhodium-catalyzed hydrogenation reactions.
نویسندگان
چکیده
Novel monodentate phosphorus ligands containing the 1,1'-spirobiindane backbone have been synthesized and applied in the asymmetric rhodium-catalyzed hydrogenation of functionalized olefins, providing excellent enantioselectivities (up to 99.3% ee).
منابع مشابه
Synthesis of new monodentate spiro phosphoramidite ligand and its application in Rh-catalyzed asymmetric hydrogenation reactions.
[reaction: see text] A new spirocyclic diol, 9,9'-spirobixanthene-1,1'-diol, was synthesized in two steps from readily available starting material m-phenoxyanisole. Resolution of the racemic diol was achieved by cocrystallization with N-benzylcinchonidinium chloride and N-benzylquininium chloride in acetonitrile. The corresponding spiro monodentate phosphoramidite ligand has been prepared for R...
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 کاملMonodentate, Supramolecular and Dynamic Phosphoramidite Ligands Based on Amino Acids in Asymmetric Hydrogenation Reactions Breuil, P.A.R
The electronic and steric effects as well as hydrogen bonds on the formation of the heteroligand complexes between monodentate amino acid based phosphoramidite and monodentate phosphine ligands were studied. Pure heterocomplex formation through the hydrogen bond between LEUPhos and a urea based phosphine is observed leading to highly active and selective catalyst. Substrate orientation through ...
متن کاملEnantioselective RH-catalyzed hydrogenation of enol acetates and enol carbamates with monodentate phosphoramidites.
[reaction: see text] Monodentate phosphoramidites, in particular PipPhos and its octahydro analogue, are excellent ligands for the rhodium-catalyzed asymmetric hydrogenation of aromatic enol acetates, enol carbamates, and 2-dienol carbamates up to 98% ee. These latter substrates were hydrogenated selectively to the carbamates of the allyl alcohol.
متن کاملPipPhos and MorfPhos: privileged monodentate phosphoramidite ligands for rhodium-catalyzed asymmetric hydrogenation.
A library of 20 monodentate phosphoramidite ligands has been prepared and applied in rhodium-catalyzed asymmetric hydrogenation. This resulted in the identification of two ligands, PipPhos and MorfPhos, that afford excellent and in several cases unprecedented enantioselectivities in the hydrogenation of N-acyldehydroamino acid esters, dimethyl itaconate, acyclic N-acylenamides, and cyclic N-acy...
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ورودعنوان ژورنال:
- Chemical communications
دوره 5 شماره
صفحات -
تاریخ انتشار 2002