   Olefin metathesis as key step in the synthesis of bioactive compounds: Challenges in the total synthesis of (-)-kendomycin; Borguet, Yannick  ; Delaude, Lionel et alin Current Organic Synthesis (2012), 9(3), 397-405 In this short review article, we highlight the application of the olefin metathesis reaction as a key step in the total synthesis of (-)-kendomycin, a macrocyclic polyketide ansamycin exhibiting ... [more ▼] In this short review article, we highlight the application of the olefin metathesis reaction as a key step in the total synthesis of (-)-kendomycin, a macrocyclic polyketide ansamycin exhibiting pronounced activity as an endothelin receptor antagonist and antiosteoporotic agent, as well as important antibiotic potency against multiresistant bacteria and remarkable cytotoxicity versus a series of human tumour cell lines. By selecting this example from the recent literature, we hope to illustrate the great synthetic ability of olefin metathesis, while also revealing some problems encountered in the syntheses. © 2012 Bentham Science Publishers. [less ▲] Detailed reference viewed: 25 (3 ULg) Metathesis access to monocyclic iminocyclitol-based therapeutic agents; ; et al in Beilstein Journal Of Organic Chemistry (2011), 7 By focusing on recent developments on natural and non-natural azasugars (iminocyclitols), this review bolsters the case for the role of olefin metathesis reactions (RCM, CM) as key transformations in the ... [more ▼] By focusing on recent developments on natural and non-natural azasugars (iminocyclitols), this review bolsters the case for the role of olefin metathesis reactions (RCM, CM) as key transformations in the multistep syntheses of pyrrolidine-, piperidine-and azepane-based iminocyclitols, as important therapeutic agents against a range of common diseases and as tools for studying metabolic disorders. Considerable improvements brought about by introduction of one or more metathesis steps are outlined, with emphasis on the exquisite steric control and atom-economical outcome of the overall process. The comparative performance of several established metathesis catalysts is also highlighted. [less ▲] Detailed reference viewed: 15 (3 ULg)Recent Applications of Alkene Metathesis in Fine Chemical SynthesisBicchielli, Dario ; Borguet, Yannick ; Delaude, Lionel et alin Dragutan, Valerian; Demonceau, Albert; Dragutan, Ileana (Eds.) et al Green Metathesis Chemistry (2010) During the last decade or so, the emergence of the metathesis reaction in organic synthesis has revolutionised the strategies used for the construction of complex molecular structures. Olefin metathesis ... [more ▼] During the last decade or so, the emergence of the metathesis reaction in organic synthesis has revolutionised the strategies used for the construction of complex molecular structures. Olefin metathesis is indeed particularly suited for the construction of small open-chain molecules and macrocycles using crossmetathesis and ring-closing metathesis, respectively. These reactions serve, inter alia, as key steps in the synthesis of various agrochemicals and pharmaceuticals such as macrocyclic peptides, cyclic sulfonamides, novel macrolides, or insect pheromones. The present chapter is aiming at illustrating the great synthetic potential of metathesis reactions. Shortcomings, such as the control of olefin geometry and the unpredictable effect of substituents on the reacting olefins, will also be addressed. Examples to be presented include epothilones, amphidinolides, spirofungin A, and archazolid. Synthetic approaches involving silicon-tethered ring-closing metathesis, relay ring-closing metathesis, sequential reactions, domino as well as tandem metathesis reactions will also be illustrated. [less ▲] Detailed reference viewed: 76 (8 ULg)Recent Advances in Ruthenium Catalysts for Alkene MetathesisDelaude, Lionel ; Demonceau, Albert ; et alin Demonceau, Albert; Dragutan, Ileana; Finkelshtein, Eugene Sh. (Eds.) et al Green Metathesis Chemistry (2010) Although ruthenium initiators currently available for alkene metathesis are endowed with many beneficial properties, there is still room for improvement and many research groups are actively pursuing the ... [more ▼] Although ruthenium initiators currently available for alkene metathesis are endowed with many beneficial properties, there is still room for improvement and many research groups are actively pursuing the quest for the next generation of alkene metathesis catalysts. The present contribution aims at providing a critical survey of some of the most significant achievements accomplished toward this goal during the last few years. New ligands and complexes designed to achieve the appropriate balance between electronic and steric properties of the ruthenium active centres are depicted, and their stability, activity, and chemoselectivity are briefly discussed. [less ▲] Detailed reference viewed: 27 (1 ULg)Exploring new achievements in olefin metathesis catalysts. Part 2 - Compelling innovations in ruthenium complexes; ; Delaude, Lionel et alin Chimica Oggi = Chemistry Today (2009), 27(3), 13-16 This part of the survey introduces recent developments on de novo designed types of ruthenium complexes used as promoters in olefin metathesis reactions. Encompassing diversity-oriented initiators not ... [more ▼] This part of the survey introduces recent developments on de novo designed types of ruthenium complexes used as promoters in olefin metathesis reactions. Encompassing diversity-oriented initiators not illustrated in Part 1, in this second part of the review emphasis is placed on the leading role played by distinct ligands in an exquisite control of metathesis reactions. [less ▲] Detailed reference viewed: 23 (4 ULg)Exploring New Achievements in olefin metathesis catalysts. Part 1 - Highlights on N-heterocyclic carbene ruthenium complexes; ; Delaude, Lionel et alin Chimica Oggi = Chemistry Today (2009), 27(3), 9-12 Most important advances in ruthenium catalysts for olefin metathesis achieved during the last 4 years are briefly reviewed. The first part of the survey focuses on new catalytic precursors endowed with ... [more ▼] Most important advances in ruthenium catalysts for olefin metathesis achieved during the last 4 years are briefly reviewed. The first part of the survey focuses on new catalytic precursors endowed with inventive N-heterocyclic carbene ligands which have proved highly proficient in a diversity of applications based on metathesis reactions. Part two extends the progress in other types of Ru initiators. [less ▲] Detailed reference viewed: 28 (8 ULg)N-heterocyclic carbene ruthenium complexes: Synthesis and catalytic properties; ; Delaude, Lionel et alin Revue Roumaine de Chimie (2007), 52(11), 1013-1025 Synthesis of imidazol(in)-2-ylidene ruthenium complexes relevant for metathesis and related catalytic processes is described. As an attractive alternative of importance for practical applications, the in ... [more ▼] Synthesis of imidazol(in)-2-ylidene ruthenium complexes relevant for metathesis and related catalytic processes is described. As an attractive alternative of importance for practical applications, the in situ generation of new NHC ruthenium precatalysts, starting from the easily accessible imidazolium and imidazolinium salts, ruthenium dimer [RuCl2(p-cymene)](2) and a base, is reported in detail. The new NHC family of ruthenium complexes offers great promise as metathesis precatalysts enjoying a wide application profile in organic and polymer synthesis. [less ▲] Detailed reference viewed: 68 (11 ULg)NHC-Ru complexes- Friendly catalytic tools for manifold chemical transformations; ; Delaude, Lionel et alin Coordination Chemistry Reviews (2007), 251(5-6), 765-794 N-Heterocyclic carbenes are now commonly encountered in organometallic and inorganic coordination chemistry. The increasing attention they enjoy is due to their ability to act as ancillary ligands in a ... [more ▼] N-Heterocyclic carbenes are now commonly encountered in organometallic and inorganic coordination chemistry. The increasing attention they enjoy is due to their ability to act as ancillary ligands in a growing number of transition metal catalysts or even to play the role of nucleophilic reagents and catalysts in diverse organic transformations. As a fine addition to the NHC-Ru-alkylidenes, popular for their tremendous success in metathesis chemistry, an array of robust and stable Ru-NHCs has proven their utility in non-metathetical reactions. The present review surveys different classes of Ru-NHCs and their applications as efficient catalysts (or precatalysts) in several types of fundamental organic processes e.g. hydrogenation, hydrogen transfer, isomerization, cycloisomerization, cyclopropanation, hydrosilylation, allylation and deallylation, enol-ester synthesis, heterocycle synthesis, C-C alkyne coupling, Kharasch addition and ATRP. A special section is devoted to tandem processes some of which include concurrent or sequential metathesis steps. Relevant mechanistic and stereochemical aspects related to NHC-Ru catalysis will be highlighted. (c) 2006 Elsevier B.V. All rights reserved. [less ▲] Detailed reference viewed: 38 (3 ULg) |
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