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ABSTRACT: Highly functionalised benzofurans have been prepared from ortho-hydroxyphenones and 1,1-dichloroethylene. The key intermediate, a chloromethylene furan, smoothly rearranged into the corresponding benzofuran carbaldehyde under acidic conditions. Some mechanistic investigations have been performed and several biologically active benzofurans have been synthesised.
Chemistry 01/2013; · 5.93 Impact Factor
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ABSTRACT: The preparation of highly functionalized benzofurans by a unique and connective transformation is reported. Base-catalyzed condensation of o-hydroxyphenones with 1,1-dichloroethylene generates the corresponding chloromethylene furans. These labile intermediates undergo a facile rearrangement into benzofuran carbaldehydes under mild acidic conditions.
Organic Letters 03/2012; 14(5):1298-301. · 5.86 Impact Factor
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Annalen der Chemie und Pharmacie 02/2011; 2011(10):1859 - 1869. · 3.10 Impact Factor
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ABSTRACT: A novel multicomponent condensation, leading to the rare (Z)-chloromethyleneketals and their sulfur analogues, has been discovered. The mechanism of this reaction has been studied in some detail and subsequent modifications were performed on the adducts, leading to unusual Umpolung transforms.
Chemical Communications 02/2011; 47(11):3287-9. · 6.17 Impact Factor
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ABSTRACT: The electrochemical reduction of diphenylphosphinate esters leads smoothly and in high yields to the corresponding deoxygenated products. In comparison with the previously developed methodologies, the electrolysis could be performed at lower temperature and with a higher current density, resulting in a shorter reaction time.
Organic Letters 02/2011; 13(3):406-9. · 5.86 Impact Factor
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ABSTRACT: The hydroxylation of Baylis-Hillman adducts 1 is shown to proceed with high levels of diastereocontrol. A mechanistic rationale to explain this selectivity is discussed.
Recueil des Travaux Chimiques des Pays-Bas. 09/2010; 114(4‐5):239 - 241.
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ABSTRACT: When catalysed by the Kobayashi: Yb(OTf)3-Binol complex, vinyl ethers and vinyl sulphides undergo highly enantioselective IEDDA reactions with 3-carbomethoxy-2-pyrone.
Bulletin des Sociétés Chimiques Belges. 08/2010; 103(5‐6):295 - 297.
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ABSTRACT: Herein, we wish to describe the efficient three-step synthesis of a novel highly hindered, but flexible, N-heterocyclic carbene and its coordination chemistry to Ag(i) and Rh(i).
Dalton Transactions 02/2010; 39(6):1444-6. · 3.84 Impact Factor
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ABSTRACT: Alcohols can be easily and chemoselectively deprotected from the corresponding aromatic esters by using either SmI(2)/HMPA or by electrolysis in the presence of a proton source.
Organic Letters 08/2009; 11(13):2752-5. · 5.86 Impact Factor
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ABSTRACT: The unexpected nucleophilic reactivity of free-radicals generated from alpha-iodoketones is reported; two different procedures, either employing tin or the more environmentally acceptable ethylsulfone-based coupling reagent have been developed.
Chemical Communications 05/2009; · 6.17 Impact Factor
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ABSTRACT: Y not? A unique, three-coordinate Y-shaped bis(silyl)platinum(II) complex was isolated and characterized (see structure; C light gray, N blue, Si pink, Pt dark gray). DFT studies on a model system shed light on the nature of this unusual coordination mode for platinum(II).
Angewandte Chemie International Edition 04/2009; 48(17):3161-4. · 13.45 Impact Factor
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ABSTRACT: The electrolysis of toluate esters leads smoothly to the formation of the radical of the alkyl fragment. This property has been used to develop a new electrochemical deoxygenation reaction.
Chemical Communications 02/2009; · 6.17 Impact Factor
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01/2009: pages 105-160; , ISBN: 978-3-13-119011-6
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ABSTRACT: The viability of the toluate moiety as a radical precursor has been examined by studying deoxygenation and cyclization reactions.
Organic Letters 08/2008; 10(13):2773-6. · 5.86 Impact Factor
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ABSTRACT: The regioselective hydrosilylation of terminal and internal alkynes catalyzed by the novel (IPr)Pt(AE) ( 7) (IPr = bis(2,6-diisopropylphenyl)imidazo-2-ylidene, AE = allyl ether) complex is presented. The (IPr)Pt(AE) catalyst displays enhanced activity and regioselectivity for the hydrosilylation of terminal and internal alkynes with low catalyst loading (0.1 to 0.05 mol %) when compared to the parent (IPr)Pt(DVDS) complex ( 6) (DVDS = divinyltetramethyldisiloxane). The reaction leads to exquisite regioselectivity in favor of the cis-addition product on the less hindered terminus of terminal and internal alkynes. The solvent effects were examined for the difficult hydrosilylation of benzylpropargyl ether. In light of the observed product distribution and kinetic data, a mechanistic scheme is proposed involving two competing catalytic cycles. One cycle leads to high regioselectivities while the other, having lost the stereodirecting IPr carbene ligand, displays low regiocontrol and activities. The importance of this secondary catalytic cycle is either caused by the strong coordinating ability of the alkyne or by the low reactivity of the silane or both.
The Journal of Organic Chemistry 07/2008; 73(11):4190-7. · 4.45 Impact Factor
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IstváN. E. Markó,
Paul R. Giles,
Masao Tsukazaki,
Arnaud Gautier,
Raphaël Dumeunier,
Kanae Doda,
Freddi Philippart,
Isabelle Chellé‐Regnault,
Jean‐Luc Mutonkole,
Stephen M. Brown,
Christopher J. Urch
02/2008: pages 437 - 478; , ISBN: 9783527619405
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ABSTRACT: The total synthesis of (R)-kavain and of the C1–C6 fragment of jerangolid D has been achieved in nine and seven steps, respectively,
from commercially available dimethyl D-malate. A metathesis reaction of vinyl ethers and a sulfoxide-modified Julia olefination have
been employed as the key steps.
Tetrahedron Letters 01/2008; 49:1523-1526. · 2.68 Impact Factor
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ABSTRACT: Bicyclic enediones of various sizes can be efficiently assembled by intramolecular Stetter cyclisation of readily available Morita-Baylis-Hillman adducts.
Chemical Communications 01/2008; · 6.17 Impact Factor
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ABSTRACT: The one-pot synthesis of useful [Pt2(0)(η4-1,6-diene)3] complexes, directly from H2PtCl6·xH2O, has remained an unaddressed problem. We have found that the treatment of an i-PrOH solution of H2PtCl6·xH2O by (Me3SiO)2MeSi(CHCH2), in the presence of allyl ether (AE), followed by reaction of the in situ generated Pt(0) species with IPr carbene (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) enables the isolation of (IPr)Pt(AE) (1) in 50−70% yield. The scope of this method has been extended to other (L)Pt(1,6-diene) complexes (L = 1,3-dicyclohexylimidazol-2-ylidene, triphenylphoshine; 1,6-diene = diethyl 2,2-diallylmalonate (DAM)), and the molecular structure of the (IPr)Pt(DAM) (4) complex has been unequivocally determined by a single-crystal X-ray diffraction analysis. These results are significant for the formation of active L−Pt(0) fragments in catalysis.
10/2007;
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ABSTRACT: The first condensations between bis(trimethylsilyloxy)cyclobutene derivatives and functionalized orthoesters are reported. The resulting adducts are readily converted into spirocycloethers, which undergo a variety of -CH2- and -O- insertions with excellent regioselectivity.
Organic Letters 10/2007; 9(19):3757-60. · 5.86 Impact Factor
