Journal ArticleDOI
Basic character of rare earth metal alkoxides. Utilization in catalytic C-C bond-forming reactions and catalytic asymmetric nitroaldol reactions
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In this article, the authors reported several carbon-carbon bond-forming reactions catalyzed by rare earth metal alkoxides and their application to a catalytic asymmetric nitroaldol reaction.Abstract:
In a recent paper, the authors reported that Zr(O-t-Bu){sub 4} was an efficient and convenient basic reagent in organic synthesis. However, all reactions examined were performed with stoichiometric quantities of the reagent. The authors envisioned that rare earth metal alkoxides would be stronger bases than group 4 metal alkoxides due to the lower ionization potential (ca. 5.4-6.4 eV) and the lower electronegativity (1.1-1.3) of rare earth elements; thus, the catalytic use of rare earth metal alkoxides in organic synthesis was expected. Although a variety of rare earth metal alkoxides have been prepared for the last three decades, to the authors knowledge, there have been few reports concerning the basicity of rare earth metal alkoxides. Herein, the authors report several carbon-carbon bond-forming reactions catalyzed by rare earth metal alkoxides and their application to a catalytic asymmetric nitroaldol reaction.read more
Citations
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Journal ArticleDOI
Organocatalytic Asymmetric Formal [3+2] Cycloaddition as a Versatile Platform to Access Methanobenzo[7]annulenes
TL;DR: Pharmaceutically and structurally important methanobenzo[7]annulenes were synthesized in very good yields with excellent enantio- and diastereoselectivities through an unprecedented organocatalytic formalcycloaddition from readily available 2-alkyl-3-hydroxynaphthalene-1,4-diones and alkyl vinyl ketones.
Journal ArticleDOI
Chiral Silver Amides as Effective Catalysts for Enantioselective [3+2] Cycloaddition Reactions
TL;DR: A silver complex prepared from silver bis(trimethylsilyl)amide (AgHMDS) and (R)-DTBM-SEGPHOS worked well in asymmetric [3+2] cycloaddition reactions of α-aminoester Schiff bases with several olefins to afford the corresponding pyrrolidine derivatives in high yields with remarkable exo- and enantioselectivities.
Journal ArticleDOI
anti-Selective Catalytic Asymmetric Nitroaldol Reaction of α-Keto Esters: Intriguing Solvent Effect, Flow Reaction, and Synthesis of Active Pharmaceutical Ingredients
TL;DR: A rare-earth metal/alkali metal bimetallic catalyst proved particularly effective for enantioselectively coupling nitroalkanes and α-keto esters in an anti-selective manner to afford synthetically versatile, densely functionalized, and optically active α-nitro tertiary alcohols.
Journal ArticleDOI
La(otf)3-catalyzed 6-endo epoxide opening of 4, 5-epoxy-4-methoxymethyl-1-hexanols
TL;DR: The selective 6-end epoxide ring opening of cis- and trans-4, 5-epoxy-4-melhoxymethyl-1-hexanols has been achieved by the chelation of La(OTf)3·nH2O between the oxygens of the epoxide and the methoxymyethyl groups to afford 3-hydroxytetrahydropyran derivatives stereospecifically as discussed by the authors.
Journal ArticleDOI
Chiral binuclear copper(II) catalyzed nitroaldol reaction: scope and mechanism
Suribabu Jammi,Prasenjit Saha,Sridhar Sanyashi,Sekarpandi Sakthivel,Tharmalingam Punniyamurthy +4 more
TL;DR: Chiral binuclear copper(II) Schiff base complexes 4a-g have been prepared from aldehydes 1a,b, (S)-amino alcohols 2a-f, and Cu(OAc)2·1H2O in high yield.
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