Enantioselective RH-catalyzed hydrogenation of enol acetates and enol carbamates with monodentate phosphoramidites.
نویسندگان
چکیده
[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.
منابع مشابه
Asymmetric hydrogenation using monodentate phosphoramidite ligands.
Monodentate phosphoramidites are excellent ligands for Rh-catalyzed asymmetric hydrogenations of substituted olefins. Enantioselectivities between 95 and 99% were obtained in the asymmetric hydrogenation of protected alpha- and beta-dehydroamino acids and esters, itaconic acid and esters, aromatic enamides, aromatic enol esters, aromatic and aliphatic enol carbamates, and alpha-substituted cinn...
متن کاملHighly enantioselective hydrogenation of enol acetates catalyzed by Ru-TunaPhos complexes.
[reaction: see text] The chiral disphosphines with tunable dihedral angles (TunaPhos) have been used for asymmetric hydrogenation of enol acetates and dihedral-angle-dependent enantioselectivities were observed. C2-TunaPhos has been proved to be effective for Ru-catalyzed asymmetric hydrogenation of electron-deficient and other enol acetates.
متن کاملAsymmetric hydrogenation of itaconic acid and enol acetate derivatives with the Rh-TangPhos catalyst.
[reaction: see text] The Rh-TangPhos catalyst has been used for asymmetric hydrogenation of itaconic acid and enol acetate derivatives. A variety of chiral 2-substituted succinic acids and chiral acetates have been obtained in excellent ee values (up to 99% ee).
متن کاملHighly enantioselective hydrogenation of enol ester phosphonates catalyzed by rhodium phosphine-phosphite complexes.
Chiral phosphine-phosphites provide versatile catalysts for the highly enantioselective hydrogenation of alpha-acyloxy alpha, beta-unsaturated phosphonates.
متن کاملAmidation of silyl enol ethers and cholesteryl acetates with chiral ruthenium(II) schiff-base catalysts: catalytic and enantioselective studies.
Chiral ruthenium(II)-salen complexes [RuII(salen)(PPh3)2] catalyse asymmetric aziridination of alkenes with up to 83% ees, asymmetric amidation of silyl enol ethers with up to 97% ees, and allylic amidation of cholesteryl acetates with good regioselectivity.
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ورودعنوان ژورنال:
- Organic letters
دوره 7 19 شماره
صفحات -
تاریخ انتشار 2005