- Palladium-catalyzed primary amine-directed regioselective mono- and di-alkynylation of biaryl-2-amines
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The first example of the palladium-catalyzed primary amine-directed C(sp2)-H alkynylation of biaryl-2-amines has been developed by using (bromoethynyl)triisopropylsilane as an alkynylating reagent. This protocol exhibits a broad substrate scope, excellent regioselectivity and gram-scale synthesis. Significantly, the versatility of this straightforward method was further demonstrated by controlled mono- and di-alkynylation.
- Jiang, Guangbin,Hu, Weigao,Li, Jianxiao,Zhu, Chuanle,Wu, Wanqing,Jiang, Huanfeng
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- Reactivity of cyclopalladated compounds derived from biphenyl-2-ylamine towards carbon monoxide, tbutyl isocyanide and alkynes
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The reactivity of the dimeric cyclopalladated compounds derived from biphenyl-2-ylamine (μ-X)2[κ2-N2′,C1-1-Pd-2-{(2′-NH2C6H4)C6H4}]2 [X = OAc (1), X = Cl (2)] towards unsaturated organic molecules is reported. Compound 1 reacted with carbon monoxide and tbutyl isocyanide producing phenanthridin-6(5H)-one and N-tert-butylphenanthridin-6-amine in 63% and 88% yield, respectively. Compound 2 reacted separately with diphenylacetylene and 3-hexyne, affording the mononuclear organopalladium compounds [κ2-N2″,C1-η2-C2,C3- 1-Pd{(R-C{double bond, long}C-R)2-2′-(2″-NH2C6H4)C6H4}Cl] [R = Ph (5), R = Et (6)] in 50-60% yield, which derived from the insertion of two alkyne molecules into the C-Pd σ bonds of 2. The crystal structure of compounds 5 and 6 has been determined. Compound 5 crystallized in the monoclinic space group P21/n with a = 13.3290(10) A?, b = 10.6610(10) A? and c = 22.3930(10) A? and β = 100.2690(10)°. Compound 6 crystallized in the triclinic space group P over(1, ?) with a = 7.271(7) A?, b = 10.038(3) A? and c = 16.012(5) A?, and α = 106.79(3)°, β = 96.25(4)° and γ = 99.62(4)°. The crystal structures of 5 and 6 have short intermolecular Pd-Cl?H-N-Pd non-conventional hydrogen bonds, which associated the molecules in chains in the first case and in dimers in the second.
- Albert, Joan,D'Andrea, Luci?a,Granell, Jaume,Zafrilla, Javier,Font-Bardia, Mercè,Solans, Xavier
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p. 4895 - 4902
(2008/03/12)
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- The cyclopalladation reaction of 2-phenylaniline revisited
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2-Phenylaniline reacted with Pd(OAc)2 in toluene at room temperature for 24 h in a one-to-one molar ratio and with the system PdCl 2, NaCl and NaOAc in a 1 (2-phenylaniline):1 (PdCl2):2 (NaCl):1 (NaOAc) molar ratio in methanol at room temperature for one week to give the dinuclear cyclopalladated compounds (μ-X)2[Pd{κ 2-N2′,C1-2-(2′-NH2C6H 4)C6H4}]2 [1a (X = OAc) and 1b (X = Cl)] in high yield. Moreover, the reaction between 2-phenylaniline and Pd(OAc)2 in one-to-one molar ratio in acid acetic at 60°C for 4 h, followed by a metathesis reaction with LiBr, allowed isolation of the dinuclear cyclopalladated compound (μ-Br)2[Pd{κ2- N2′,C1-2-(2′-NH2C6H4)C 6H4}]2 (1c) in moderate yield. A parallel treatment, but using monodeuterated acetic acid (DOAc) as solvent in the cyclopalladation reaction, allowed isolation of a mixture of compounds 1c, 1cd1 [Pd{κ2-N2′,C1-2-(2′-NH 2C6H4)C6H4](μ-Br) 2[Pd{κ2-N2′,C1-2-(2′-NH 2C6H4)-3-d-C6H3] and 1cd2 (μ-Br)2[Pd{κ2-N2′,C1-2- (2′-NH2C6H4)-3-d-C6H 3}]2 in moderate yield and with a deuterium content of ca. 60%. 1a and 1b reacted with pyridine and PPh3 affording the mononuclear cyclopalladated compounds [Pd{κ2-N2′,C1-2- (2′-NH2C6H4)C6H 4}(X)(L)] [2a (X = OAc, L = py), 2b (X = Cl, L = py), 3a (X = OAc, L = PPh3) and 3b (X = Cl, L = PPh3)] in a yield from moderate to high. Furthermore, 1a reacted with Na(acac) ? H2O to give the mononuclear cyclopalladated compound 4 [Pd{κ2- N2′,C1-2-(2′-NH2C6H4)C 6H4}(acac)] in moderate yield. 1H NMR studies in CDCl3 solution of 2a, 2b, 3a, 3b and 4 showed that 2a and 3a presented an intramolecular hydrogen bond between the acetato ligand and the amino group, and were involved in a dynamic equilibrium with water present in the CDCl3 solvent; and that the enantiomeric molecules of 2b and 4 were in a fast exchange at room temperature, while they were in a slow exchange for 2a, 3a and 3b. The X-ray crystal structures of 3b and 4 were determined. 3b crystallized in the triclinic space group P1? with a = 9.9170(10), b = 10.4750(10), c = 12.0890(10) A?, α = 98.610(10)°, β = 94.034(10)°and γ = 99.000(10)°and 4 in the monoclinic space group P21/a with a = 11.5900(10), b = 11.2730(10), c = 12.2150(10) A?, α = 90°, β = 107.6560(10)°and γ = 90°.
- Albert, Joan,Granell, Jaume,Zafrilla, Javier,Font-Bardia, Mercè,Solans, Xavier
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p. 422 - 429
(2007/10/03)
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