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Enantio‐ and Diastereoselective Synthesis of Chiral Allenes by Palladium‐Catalyzed Asymmetric [3+2] Cycloaddition Reactions
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Prof. Dr. Barry M. Trost Dr. Daniel Zell Dr. Christoph Hohn Dr. Guillaume Mata Autumn Maruniak 《Angewandte Chemie (International ed. in English)》2018,57(39):12916-12920
A protocol for the asymmetric synthesis of highly substituted chiral allenes with control of point and axial chirality has been developed. A palladium‐catalyzed [3+2] cycloaddition using readily available racemic allenes gives access to densely functionalized chiral allenes with excellent yields and functional group tolerance. The catalytic asymmetric protocol utilizes a broad range of allenyl TMM (trimethylenemethane) donors to form cyclopentanes, pyrrolidines, and spirocycles with very good control of regio‐, enantio‐, and diastereoselectivity. The chiral allene moiety is shown to be a valuable functional group for rapid elaboration towards complex targets. 相似文献
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Gorka Garay Josebe Hurtado Manuel Pedrón Lorena García Dr. Efraim Reyes Eduardo Sánchez-Díez Prof. Dr. Tomás Tejero Prof. Dr. Luisa Carrillo Prof. Dr. Pedro Merino Prof. Dr. Jose L. Vicario 《Angewandte Chemie (International ed. in English)》2023,62(22):e202302416
We have demonstrated that the catalytic and enantioselective vinylcyclopropane-cyclopentene rearrangement can be carried out on (vinylcyclopropyl)acetaldehydes through activation via enamine intermediates. The reaction makes use of racemic starting materials that, upon ring opening facilitated by the catalytic generation of a donor-acceptor cyclopropane, deliver an acyclic iminium ion/dienolate intermediate in which all stereochemical information has been deleted. The final cyclization step forms the rearrangement product, showing that chirality transfer from the catalyst to the final compound is highly effective and leads to the stereocontrolled formation of a variety of structurally different cyclopentenes. 相似文献
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Hélène PellissierAuthor Vitae 《Tetrahedron》2011,67(21):3769-3802
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Simon Hilker Dr. Daniels Posevins Prof. Dr. C. Rikard Unelius Prof. Dr. Jan-E. Bäckvall 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(63):15623-15627
Herein we report on the development and application of chemoenzymatic Dynamic Kinetic Asymmetric Transformation (DYKAT) of α-substituted β-hydroxyketones (β-HKs), using Candida antartica lipase B (CALB) as transesterification catalyst and a ruthenium complex as epimerization catalyst. An operationally simple protocol allows for an efficient preparation of highly enantiomerically enriched α-substituted β-oxoacetates. The products were obtained in yields up to 95 % with good diastereomeric ratios. 相似文献
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Efraim Reyes 《Tetrahedron letters》2005,46(39):6605-6609
The ability of amino acids to catalyze dynamic kinetic asymmetric transformation (DYKAT) with excellent stereoselectivity is presented. The novel DYKAT process was applied in the proline-catalyzed one-step de novo synthesis of triketide- and deoxysugars, which were formed with excellent diastereoselectivity and up to 99% ee. The de novo synthesis is accomplished via an enzyme-like DYKAT process, which includes continuous amino acid-mediated racemization of the acceptor β-hydroxy aldehyde in combination with amino acid-catalyzed direct selective aldol addition. 相似文献
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