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Showing papers in "Organic Letters in 2004"


Journal ArticleDOI
TL;DR: The C3-symmetric derivative of polytriazolylamines, TBTA, was shown to be a powerful stabilizing ligand for copper(I), protecting it from oxidation and disproportionation, while enhancing its catalytic activity.

1,344 citations


Journal ArticleDOI
TL;DR: Copper(I)-catalyzed 1,3-dipolar cycloaddition reaction of nonfluorescent 3-azidocoumarins and terminal alkynes afforded intense fluorescent 1,2, 3-triazole products, which has potential in bioconjugation and bioimaging applications.

666 citations


Journal ArticleDOI
TL;DR: A microwave-assisted three-component reaction was used to prepare a series of 1,4-disubstituted-1,2,3-triazoles from corresponding alkyl halides, sodium azide, and alkynes, eliminating the need to handle organic azides.

517 citations


Journal ArticleDOI
TL;DR: An efficient palladium-catalyzed carbon-sulfur bond formation reaction of aryl bromides, triflates, and activated aryL chloride is developed that has shown tolerance to a wide variety of aries and alkyl thiols that can also be used as sulfide equivalents.

434 citations


Journal ArticleDOI
TL;DR: Well-defined color change in the visible region of the spectrum was observed upon addition of fluoride ion in DMSO/CH3CN solution of the receptors 1 and 2.

418 citations


Journal ArticleDOI
TL;DR: While monitoring the conversion via (1)H NMR spectroscopy, an intermediate 5-methylene-4,5-dihydrooxazole can be observed and accumulated up to 95%, being the first direct and catalytic preparative access to such alkylidene oxazolines.

372 citations


Journal ArticleDOI
TL;DR: A simple, high-yielding synthesis of 2,4,5-trisubstituted imidazoles from 1,2-diketones and aldehydes in the presence of NH(4)OAc is described.

368 citations


Journal ArticleDOI
Wensheng Yu1, Yan Mei1, Ying Kang1, Zhengmao Hua1, Zhendong Jin1 
TL;DR: It is found that the addition of 2,6-lutidine can suppress the side reactions and dramatically improve the yield of this classic reaction.

359 citations


Journal ArticleDOI
TL;DR: The aza-Henry reaction of imines with nitroalkanes was promoted by chiral thiourea with an N,N-dimethylamino group to give beta-nitroamines with good enantioselectivity.

326 citations


Journal ArticleDOI
TL;DR: The construction of chiral carbon centers via the first catalytic asymmetric alkynylation of prochiral CH2 groups was developed by using a copper-catalyzed double activation of sp3 and sp C-H bonds.

314 citations


Journal ArticleDOI
TL;DR: 1,4-Disubstituted 1,2,3-triazoles are obtained in excellent yields by a convenient one-pot procedure from a variety of readily available aromatic and aliphatic halides without isolation of potentially unstable organic azide intermediates.

Journal ArticleDOI
TL;DR: Two Colorimetric azobenzene based chemosensors 1 and 2 were designed for detection of transition-metal ions such as Cu(II) under physiological pH conditions and give rise to red-to-yellow color changes that are visible to the naked-eye and reversible upon addition of EDTA.

Journal ArticleDOI
TL;DR: It is demonstrated, for the first time, that the reaction of toluene and nitric acid in three different ionic liquids gives rise to three completely different products in high yield.

Journal ArticleDOI
TL;DR: In this article, the α,α-dialkylaldehydes with (E)-β-nitrostyrene provided the α-α-dynamic Michael products in up to 96% yield with up to 91% ee.

Journal ArticleDOI
TL;DR: A practical cross-coupling of amides with alkynyl bromides using catalytic CuSO(4).5H(2)O and 1,10-phenanthroline is described here and provides a general entry for syntheses of ynamides including various new sulfonyl and heteroaromatic amine substituted ynamide.

Journal ArticleDOI
TL;DR: An efficient method for the synthesis of diaryl ethers under particularly mild conditions is described, and inexpensive ligands were found to greatly accelerate the Ullmann-type coupling of aryl bromides or iodides with phenols.

Journal ArticleDOI
TL;DR: Mechanistic studies unambiguously support an electrophilic substitution pathway for palladium-catalyzed selective arylation and heteroarylation of indolizines at C-3.

Journal ArticleDOI
Lei Shi1, Yong-Qiang Tu1, Min Wang1, Fu-Min Zhang1, Chun-An Fan1 
TL;DR: The preliminary experiment using (S)-proline methyl ester as a chiral source demonstrated that it could be developed to be a direct and highly diastereoselective method for construction of chiral propargylamines.

Journal ArticleDOI
TL;DR: Tris(acetylacetonato)iron(III) (Fe(acac)(3)) was found to be an efficient catalyst for the cross-coupling reaction between aryl Grignard reagents and alkyl halides possessing beta-hydrogens.

Journal ArticleDOI
TL;DR: An unexpected, interesting effect results from the introduction of a third C=C onto the ligand scaffold that results in high selectivity in Rh(I)-catalyzed conjugate addition reactions to substrates not previously examined with diene ligands.

Journal ArticleDOI
TL;DR: Novel octupolar fluorophores derived from the symmetrical functionalization of a triphenylamine core with strong acceptor peripheral groups via phenylene-ethynylene linkers have been synthesized and shown to exhibit high fluorescence quantum yields, very large TPA cross-sections in the red-NIR region, and suitable photostability.

Journal ArticleDOI
TL;DR: Much improved yields were obtained for a wide array of azides and alkynes in the regioselective synthesis of 1,5-disubstituted-1,2,3-triazoles via the addition of bromomagnesium acetylides to azides.

Journal ArticleDOI
TL;DR: A new, practical method by which N-substituted indoles may be selectively arylated in the C2-position with good yields, low catalyst loadings, and a high degree of functional group tolerance is presented.

Journal ArticleDOI
TL;DR: A method for the synthesis of vinyl sulfides using the soluble copper(I) catalyst [Cu(phen)(PPh3)2]NO3 is reported, which tolerates a wide variety of functional groups or substrates, is palladium-free, and does not require the use of expensive or air-sensitive additives.

Journal ArticleDOI
TL;DR: A new efficient method for the N-heterocyclization of primary amines with diols catalyzed by a CpIr complex was developed and a variety of five-, six-, and seven-membered cyclic amines were synthesized in good to excellent yields with the formation of only water as a byproduct.

Journal ArticleDOI
TL;DR: A series of crystalline acenedithiophenes with up to seven linearly fused rings and silylethynyl substituents are reported, designed to both improve solubility and enhance cofacial interactions in the solid.

Journal ArticleDOI
TL;DR: An aqueous biphasic reaction system enables the direct use of allylcohol in the Tsuji-Trost reaction without the help of any activating reagents for allyl alcohol.

Journal ArticleDOI
TL;DR: A new pseudorotaxane was designed and synthesized on the basis of viologen-CB7 binding interactions and its mode of interaction is different with longer chain viologens due to the favorable hydrophobic interactions between the terminal alkyl substituents and the inner cavity of the host.

Journal ArticleDOI
TL;DR: L-Proline-based small peptides have been developed as efficient catalysts for the asymmetric direct aldol reactions of hydroxyacetone with aldehydes and chiral 1,4-diols 7 were obtained in high yields and enantioselectivities in aqueous media.

Journal ArticleDOI
TL;DR: A preliminary mechanistic investigation of the rhodium-catalyzed arylation of a variety of heterocycles revealed the intermediacy of an isolable N-heterocyclic carbene complex.