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
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Enantioselective synthesis of α-hydroxy phosphonates using the LaLi3tris(binaphthoxide) catalyst (LLB), prepared by an improved method
TL;DR: In this article, the LaLi 3 tris(binaphthoxide) catalyst (LLB) was used for the hydrophosphonylation of various aldehydes to give desired α-hydroxyphosphonates in up to 95% ee (88% yield).
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Convenient Transformation of Optically Active Nitroalkanes into Chiral Aldoximes and Nitriles
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Organocatalytic Asymmetric Nitroaldol Reaction: Cooperative Effects of Guanidine and Thiourea Functional Groups
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TL;DR: On the basis of studies of structure and catalytic-activity relationships, a plausible guanidine-thiourea cooperative mechanism and a transition state of the catalytic reactions are proposed and may lead to the development of new chiral surfactants.
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A Highly Diastereo- and Enantioselective Copper(I)-Catalyzed Henry Reaction Using a Bis(sulfonamide)−Diamine Ligand
Wei Jin,Xincheng Li,Boshun Wan +2 more
TL;DR: With the assistance of pyridine, a CuBr-3a system promotes the diastereoselective Henry reaction with various aldehyde substrates and gives the corresponding syn-selective adduct with up to a 99% yield and 32.3:1 syn/anti selectivity.
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Catalytic asymmetric Henry reactions of silyl nitronates with aldehydes
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