Journal ArticleDOI
Catalyst-controlled asymmetric synthesis of fostriecin and 8-epi-fostriecin.
Keisuke Maki,Rie Motoki,Kunihiko Fujii,Motomu Kanai,Takayasu Kobayashi,Shinri Tamura,Masakatsu Shibasaki +6 more
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TLDR
All the stereocenters were constructed under catalyst control in this synthesis and should be useful for rapid synthesis of stereoisomers of fostriecin.Abstract:
Catalytic asymmetric synthesis of the natural antibiotic fostriecin (CI-920) and its analogue 8-epi-fostriecin and evaluation of their biological activity are described. We used four catalytic asymmetric reactions to construct all of the chiral centers of fostriecin and 8-epi-fostriecin; cyanosilylation of a ketone, Yamamoto allylation, direct aldol reaction, and Noyori reduction, two of which were developed by our group. Catalytic enantioselective cyanosilylation of ketone 13 produced the chiral tetrasubstituted carbon at C-8. Both enantiomers of the product cyanohydrin were obtained with high enantioselectivity by switching the center metal of the catalyst from titanium to gadolinium. Yamamoto allylation constructed the C-5 chiral carbon in the alpha,beta-unsaturated lactone moiety. A direct catalytic asymmetric aldol reaction of an alkynyl ketone using LLB catalyst constructed the chirality at C-9 with the introduction of a synthetically versatile alkyne moiety, which was later converted to cis-vinyl iodide, the substrate for the subsequent Stille coupling for the triene synthesis. Noyori reduction produced the secondary alcohol at C-11 from the acetylene ketone 6 with excellent selectivity. Importantly, all the stereocenters were constructed under catalyst control in this synthesis. This strategy should be useful for rapid synthesis of stereoisomers of fostriecin.read more
Citations
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The Direct Catalytic Asymmetric Aldol Reaction
TL;DR: This critical review documents the development of direct catalytic asymmetric aldol methodologies, including organocatalytic and metal-based strategies, which have improved the reactivity, selectivity and substrate scope of the direct a Aldol reaction and enabled the synthesis of complex molecular targets.
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Catalytic enantioselective allylation of carbonyl compounds and imines.
Journal ArticleDOI
Enantioselective Catalytic Formation of Quaternary Stereogenic Centers
TL;DR: In this article, the authors discuss recent highlights of this new direction in catalysis research: the formation of quaternary stereogenic centers by enantioselective catalytic methodologies.
Journal ArticleDOI
Recent progress in asymmetric bifunctional catalysis using multimetallic systems.
TL;DR: Recent advances in enantioselective catalysis with bifunctional catalysts are described, focusing on the development of asymmetric catalysts that exhibit high activity, selectivity, and broad substrate generality under mild reaction conditions.
Journal ArticleDOI
Modern aldol methods for the total synthesis of polyketides.
Bernd Schetter,Rainer Mahrwald +1 more
TL;DR: This Review illustrates by means of selected syntheses of natural products the new variants of the aldol addition, which includes a Aldol additions with various metal enolates, as well as metal-complex-catalyzed, organocatalytic, and biocatalysis methods.
References
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Synthesis and activity of a new generation of ruthenium-based olefin metathesis catalysts coordinated with 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene ligands.
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Recent advances in olefin metathesis and its application in organic synthesis
Robert H. Grubbs,Sukbok Chang +1 more
TL;DR: In this paper, a review of recent advances in olefin metathesis focusing on the areas of ring-closing olefi cation (RCM) and cross-metathesis is presented.
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Asymmetric Catalysis with Heterobimetallic Compounds
TL;DR: In this paper, the authors describe the development of rare-earth-alkali metal complexes such as LnM3tris(binaphthoxide) complexes (LnMB, Ln = rare earth metal, M = alkali metal), which are readily prepared from corresponding rare earth trichlorides or rare earth isopropoxides, and their application to catalytic asymmetric synthesis.
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Asymmetric Transfer Hydrogenation of α, β-Acetylenic Ketones
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Characterization of microcystin-LR, a potent inhibitor of type 1 and type 2A protein phosphatases.
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