- Synthesis of Enantiomerically Pure β-Hydroxy Ketones via β-Keto Weinreb Amides by a Condensation/Asymmetric-Hydrogenation/Acylation Sequence
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An established route to enantiomerically pure β-hydroxy ketones proceeds through the asymmetric hydrogenation of β-keto esters, an ester/amide exchange, and the use of the resulting β-hydroxy amide for the acylation of an organometallic compound. We shortened this route by showing that β-keto Weinreb amides are hydrogenated with up to 99 % ee in the presence of [Me2NH2]+{[RuCl(S)-BINAP]2(μ-Cl)3}–(0.5 mol-%) at room temp./5 bar. These Weinreb amides were prepared by seemingly obvious yet unprecedented condensations of lithiated N-methoxy-N-methylacetamide with carboxylic chlorides (51–87 % yield). The resulting β-hydroxy Weinreb amides were used for the acylation of organolithium and Grignard reagents. They thus gave enantiomerically pure β-hydroxy ketones (28 examples). A selection of these compounds gave anti-1,3-diols after another C=O bond hydrogenation, or syn-1,3-diols by a Narasaka–Prasad reduction.
- Diehl, Julian,Brückner, Reinhard
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supporting information
p. 278 - 286
(2017/01/24)
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- Synthesis of the C2-symmetric 1,3-dicyclohexyl-1,3-propanediol and diamine enantiomers
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The parent C2-symmetric (R,R)- and (S,S)-1,3-dicyclohexyl-1,3- propanediols and diamines are readily obtained from the corresponding diphenyldiol precursors.
- Donovan, A. Richard,Roos, Gregory H.P.
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p. 3685 - 3692
(2007/10/03)
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- Chiral 1,2-bis(phosphetano)benzenes: Preparation and use in the Ru- catalyzed hydrogenations of carbonyl derivatives
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Chiral 1,2-bis(phosphetano)benzenes are readily prepared from accessible, optically pure 1,3-diol cyclic sulfates. Their ruthenium complexes catalyze the enantioselective hydrogenations of functionalized carbonyls with moderate-to-high enantiomeric excesses. High levels of diastereo- and enantioselectivity are achieved, especially in the hydrogenation of β-diketones to the corresponding anti-1,3-diols.
- Marinetti, Angela,Genet, Jean-Pierre,Jus, Sebastien,Blanc, Delphine,Ratovelomanana-Vidal, Virginie
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p. 1160 - 1165
(2007/10/03)
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- Enantioselective synthesis ofanti 1, 3-diols via ru(ii)-catalyzed hydrogénations
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The homogeneous ruthenium-catalyzed hydrogénation of new symmetrical 1, 3-diketones has been achieved with various ligands including SKEWPHOS and Me-DuPHOS. Complete conversions with enantiomeric and diastereomeric excesses up to 99% were obtained. This represents a new catalytic application of the chiral ligands above. Thieme Stuttgart.
- Blanc, Delphine,Ratovelomanana-Vidai, Virginie,Marinetti, Angela,Genêt, Jean-Pierre
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p. 480 - 482
(2007/10/03)
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