The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Shu-li You - One of the best experts on this subject based on the ideXlab platform.
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N‑Heterocyclic Carbene-Catalyzed Enantioselective Intramolecular N‑Tethered Aldehyde–Ketone Benzoin Reactions
2016Co-Authors: Minqiang Jia, Shu-li YouAbstract:The N-Heterocyclic Carbene-catalyzed enantioselective intramolecular benzoin reaction of N-tethered substrates was realized. With 15 mol % of d-camphor-derived triazolium salt E and 10 mol % of NaOAc, the aldehyde–ketone cross benzoin reactions of various substituted N-tethered substrates proceeded smoothly to afford dihydroquinolinone derivatives with a quaternary carbon stereocenter in moderate to good yields and excellent ee
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n heterocyclic Carbene catalyzed enantioselective intramolecular n tethered aldehyde ketone benzoin reactions
ACS Catalysis, 2013Co-Authors: Minqiang Jia, Shu-li YouAbstract:The N-Heterocyclic Carbene-catalyzed enantioselective intramolecular benzoin reaction of N-tethered substrates was realized. With 15 mol % of d-camphor-derived triazolium salt E and 10 mol % of NaOAc, the aldehyde–ketone cross benzoin reactions of various substituted N-tethered substrates proceeded smoothly to afford dihydroquinolinone derivatives with a quaternary carbon stereocenter in moderate to good yields and excellent ee.
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enantioselective n heterocyclic Carbene catalyzed michael addition to α β unsaturated aldehydes by redox oxidation
Organic Letters, 2011Co-Authors: Ziqiang Rong, Minqiang Jia, Shu-li YouAbstract:Enantioselective N-Heterocyclic Carbene-catalyzed Michael addition reactions to α,β-unsaturated aldehydes by redox oxidation were realized. With 10 mol % of camphor-derived triazolium salt D, 15 mo...
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n heterocyclic Carbene catalyzed ring expansion of formylcyclopropanes synthesis of 3 4 dihydro α pyrone derivatives
Organic Letters, 2009Co-Authors: Lixin Dai, Shu-li YouAbstract:N-Heterocyclic Carbene catalyzed ring expansion of readily accessible 2-acyl-1-formylcyclopropanes was developed. With 5 mol % of triazolium salt 5 and 30 mol % of DBU, ring expansion of various 2-acyl-1-formylcyclopropanes led to 3,4-dihydro-α-pyrones in good to excellent yields.
Frank Glorius - One of the best experts on this subject based on the ideXlab platform.
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efficient synthesis of benzofuranones n heterocyclic Carbene nhc base catalyzed hydroacylation stetter rearrangement cascade
Organic Letters, 2011Co-Authors: Mohan Padmanaban, Akkattu T. Biju, Frank GloriusAbstract:A N-Heterocyclic Carbene/base-catalyzed cascade reaction leading to the formation of functionalized benzofuranones is reported. The reaction proceeds via an intramolecular hydroacylation of unactivated alkynes followed by an intermolecular Stetter reaction and a base-catalyzed chromanone to benzofuranone rearrangement.
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dual activation in n heterocyclic Carbene organocatalysis
Chemistry Letters, 2011Co-Authors: Keiichi Hirano, Isabel Piel, Frank GloriusAbstract:N-Heterocyclic Carbene (NHC)-catalyzed transformations have found increasing interest in the last years. Recently, dual catalytic approaches using NHCs in combination with a second catalyst such as...
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n heterocyclic Carbene catalyzed cascade reaction involving the hydroacylation of unactivated alkynes
ChemInform, 2010Co-Authors: Akkattu T. Biju, Nathalie E Wurz, Frank GloriusAbstract:The N-Heterocyclic Carbene (NHC)-catalyzed hydroacylation of unactivated alkynes to provide α,β-unsaturated ketones is reported. In addition, a rare case of an efficient and selective dually NHC-catalyzed cascade reaction involving the hydroacylation of alkynes and a subsequent intermolecular Stetter reaction allows the formation of chromanones containing a 1,4-diketone moiety.
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imidazo 1 5 a pyridine 3 ylidenes pyridine derived n heterocyclic Carbene ligands
Tetrahedron, 2005Co-Authors: Christian Burstein, Christian W Lehmann, Frank GloriusAbstract:Abstract The ready synthesis of differently substituted 2H-imidazo[1,5-a]pyridin-4-ium bromides is reported. These salts are precursors for a new class of N-Heterocyclic Carbene ligands. As a consequence of their bicyclic geometry, these ligands are capable of influencing the coordination sphere of a Carbene bound metal. The usefulness of these ligands was demonstrated in the palladium-catalyzed Suzuki–Miyaura cross-coupling of sterically hindered aryl chlorides.
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oxazolines as chiral building blocks for imidazolium salts and n heterocyclic Carbene ligands
Chemical Communications, 2002Co-Authors: Frank Glorius, Gereon Altenhoff, Richard Goddard, Christian W LehmannAbstract:Enantiomerically pure imidazolium triflates can be readily prepared from bioxazolines and oxazolineimines; deprotonation of imidazolium triflate 2 gives a chiral N-Heterocyclic Carbene that can act as a ligand in a catalytically active palladium complex.
Dennis P Curran - One of the best experts on this subject based on the ideXlab platform.
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facile synthesis of α n heterocyclic Carbene boryl ketones from n heterocyclic Carbene boranes and alkenyl triflates
Journal of the American Chemical Society, 2019Co-Authors: Wen Dai, Steven J Geib, Dennis P CurranAbstract:Reactions of readily available alkenyl triflates with N-Heterocyclic Carbene (NHC)-boranes in the presence of diisopropyl ethyl amine provided about three dozen stable α-NHC-boryl ketones. Isolated...
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radical trans hydroboration of alkynes with n heterocyclic Carbene boranes
Angewandte Chemie, 2018Co-Authors: Masaki Shimoi, Dennis P Curran, Takashi Watanabe, Katsuhiro Maeda, Tsuyoshi TaniguchiAbstract:Hydroboration of internal alkynes with N-Heterocyclic Carbene boranes (NHC-boranes) occurs to provide stable NHC (E)-alkenylboranes upon thermolysis in the presence of di-tert-butyl peroxide. The E isomer results from an unusual trans-hydroboration, and the E/Z selectivity is typically high (90:10 or greater). Evidence suggests that this hydroboration occurs by a radical-chain reaction involving addition of an NHC-boryl radical to an alkyne to give a β-NHC-borylalkenyl radical. Ensuing hydrogen abstraction from the starting NHC-borane provides the product and returns the starting NHC-boryl radical. Experiments suggest that the observed trans-selectivity results from kinetic control in the hydrogen-transfer reaction.
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Molecular Iodine Initiates Hydroborations of Alkenes with N‑Heterocyclic Carbene Boranes
2016Co-Authors: Xiangcheng Pan, Anne Boussonnière, Dennis P CurranAbstract:The hydroboration of alkenes of diverse structural types by assorted N-Heterocyclic Carbene boranes can be accomplished by addition of 5–10% diiodine. For example, reaction of 1,3-dimethylimidazol-2-ylidene borane (diMe-Imd-BH3) with 10% I2 followed by addition of 2,3-dimethyl-2-butene provided the corresponding thexyl NHC-borane (diMe-Imd-BH2thexyl) in 75% yield. This and related monohydroboration products are stable to chromatography and storage. The scope of the new reaction is described, and the mechanism is probed by 11B NMR experiments
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hydroboration of arynes with n heterocyclic Carbene boranes
Angewandte Chemie, 2014Co-Authors: Tsuyoshi Taniguchi, Dennis P CurranAbstract:Arynes were generated in situ from ortho-silyl aryl triflates and fluoride ions in the presence of stable N-Heterocyclic Carbene boranes (NHC-BH3). Spontaneous hydroboration ensued to provide stable B-aryl-substituted NHC-boranes (NHC-BH2Ar). The reaction shows good scope in terms of both the NHC-borane and aryne components and provides direct access to mono- and disubstituted NHC-boranes. The formation of unusual ortho regioisomers in the hydroboration of arynes with an electron-withdrawing group supports a hydroboration process with hydride-transfer character.
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Molecular iodine initiates hydroborations of alkenes with N-Heterocyclic Carbene boranes.
Journal of the American Chemical Society, 2013Co-Authors: Xiangcheng Pan, Anne Boussonnière, Dennis P CurranAbstract:The hydroboration of alkenes of diverse structural types by assorted N-Heterocyclic Carbene boranes can be accomplished by addition of 5–10% diiodine. For example, reaction of 1,3-dimethylimidazol-2-ylidene borane (diMe-Imd-BH3) with 10% I2 followed by addition of 2,3-dimethyl-2-butene provided the corresponding thexyl NHC-borane (diMe-Imd-BH2thexyl) in 75% yield. This and related monohydroboration products are stable to chromatography and storage. The scope of the new reaction is described, and the mechanism is probed by 11B NMR experiments.
Masato Suzuki - One of the best experts on this subject based on the ideXlab platform.
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expanding the scope of the tail to tail dimerization of vinyl compounds catalyzed by n heterocyclic Carbene
Bulletin of the Chemical Society of Japan, 2015Co-Authors: Shinichi Matsuoka, Masanori Nakazawa, Masato SuzukiAbstract:The tail-to-tail dimerization of vinyl compounds catalyzed by an N-Heterocyclic Carbene was found to show a very broad substrate scope and tolerance to various functional groups. The optimization o...
Steven P Nolan - One of the best experts on this subject based on the ideXlab platform.
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n heterocyclic Carbene nhc ligands and palladium in homogeneous cross coupling catalysis a perfect union
Chemical Society Reviews, 2011Co-Authors: George C Fortman, Steven P NolanAbstract:Cross-coupling reactions using Pd-NHC (NHC = N-Heterocyclic Carbene) catalysts are discussed in this critical review and examined in terms of catalytic activity and how these have permitted advances in the area as they developed (95 references).
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carboxylation of c h bonds using n heterocyclic Carbene gold i complexes
Journal of the American Chemical Society, 2010Co-Authors: Ine I F Boogaerts, Steven P NolanAbstract:A highly efficient [(NHC)AuI]-based (NHC = N-Heterocyclic Carbene) catalytic system for the carboxylation of aromatic and heteroaromatic C−H bonds was developed. The significant base strength of the Au−OH species is at the origin of the activation process and permits the facile functionalization of C−H bonds without the use of other organometallic reagents.
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a n heterocyclic Carbene gold hydroxide complex a golden synthon
Chemical Communications, 2010Co-Authors: Sylvain Gaillard, Alexandra M Z Slawin, Steven P NolanAbstract:The synthesis and complete characterisation of a well-defined N-Heterocyclic Carbene bearing gold hydroxide complex, [Au(OH)(IPr)], is reported. Its reaction chemistry appears rich and diverse.
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activation and reactivity of nhc pd allyl cl nhc n heterocyclic Carbene complexes in cross coupling reactions
Organometallics, 2002Co-Authors: Mihai S Viciu, Romain F Germaneau, O Navarrofernandez, Edwin D Stevens, Steven P NolanAbstract:Mononuclear palladium-allyl complexes bearing one N-Heterocyclic Carbene (NHC) ligand have been synthesized. These complexes offer a straightforward entryway into a number of catalytic cycles by simple action of a base.