- Deprotonation of thiophenes using lithium magnesates
-
Thiophene was regioselectively deprotonated at C2 on treatment with 1/3 equiv of Bu3MgLi in THF at room temperature. The lithium arylmagnesate formed was either trapped with electrophiles or cross-coupled in a 'one-pot' procedure with aryl halides under palladium catalysis. 2-Chlorothiophene and 2-methoxythiophene were similarly deprotonated at C5 under the same reaction conditions. The enhancement of the reactivity of the base using TMEDA was evidenced using 1H NMR spectroscopy.
- Bayh, Omar,Awad, Ha?an,Mongin, Florence,Hoarau, Christophe,Trécourt, Fran?ois,Quéguiner, Guy,Marsais, Francis,Blanco, Fernando,Abarca, Belén,Ballesteros, Rafael
-
-
Read Online
- Synthesis of unsymmetrical heterobiaryls using palladium-catalyzed cross-coupling reactions of lithium organozincates
-
Several unsymmetrical heterobiaryls have been synthesized through palladium-catalyzed cross-coupling reactions of lithium triorganozincates. The latter have been prepared by deprotonative lithiation followed by transmetalation using non-hygroscopic ZnCl2-TMEDA (0.33 equiv). Georg Thieme Verlag Stuttgart.
- Seggio, Anne,Jutand, Anny,Priem, Ghislaine,Mongin, Florence
-
-
Read Online
- Metal-ion dependent reactivity of 2-(2'-thienyl)pyridine (Hthpy)
-
The reaction of 2-(2'thienyl)pyridine (Hthpy) with palladium acetate results in a clean conversion to the μ-acetato-bridged dimeric cyclometallated complex in which a new Pd-C bond is formed at the 3' position of the thienyl ring.In contrast, treatment with Na under similar conditions only results in the formation of the complex in which the ligand acts as a monodentate N-donor.At higher temperatures the reaction of Na with Hthpy yields a complex mixture of products, including complexes of 2-(5'-chloro-2'-thienyl)pyridine and 5,5'-bis(2-pyridyl)-2,2'-bithienyl.Independent syntheses of these latter compounds have confirmed their identities.The reaction of 2-(2'thienyl)pyridine with (bpy = 2,2'-bypyridine) in the presence of a chloride ion abstractor yields salts of the cation 2+ which contains a bidentate N,S-bonded ligand.
- Constable, Edwin C.,Sousa, Lynn R.
-
-
Read Online
- Rhodium-Catalyzed N-tert-Butoxycarbonyl (Boc) Amination by Directed C H Bond Activation
-
N-tert-Butoxycarbonyl azide (BocN3) was shown to be an efficient and economic source for the directed introduction of N-Boc protected amino groups into the thiophene and benzene nucleus. Yields for the amination of 2-pyridin-2-ylthiophenes (10 examples) were 52–88%. For the amination of the respective benzenes (10 examples) yields between 54% and 99% were recorded with an improved reactivity observed for substrates that bear an electron-withdrawing group. The reaction was applied to short total syntheses of the indoloquinoline alkaloids quindoline and cryptolepine. The facile removal of the Boc protecting group was the key to the success of the syntheses. The scope of the reaction was extended to a C(sp3) H bond amination and to the amination of 2-phenyloxazoline. For the amination of 2-pyridin-2-ylbenzene a kinetic deuterium isotope effect of 2.0 was determined. (Figure presented.) .
- Wippich, Julian,Truchan, Nadina,Bach, Thorsten
-
supporting information
p. 2083 - 2087
(2016/07/16)
-
- Pd-catalyzed oxidative C-H/C-H cross-coupling of pyridines with heteroarenes
-
We have developed for the first time a general, concise and highly selective method for the C2-heteroarylation of pyridines and related azines with a broad range of heteroarenes via a two-fold C-H activation, which streamlines the previous approaches that require the activated azine N-oxide as the coupling partner.
- Liu, Bo,Huang, Yumin,Lan, Jingbo,Song, Feijie,You, Jingsong
-
p. 2163 - 2167
(2013/05/09)
-
- Palladium-catalyzed cross-couplings of lithium arylzincates with aromatic halides: Synthesis of analogues of isomeridianin G and evaluation as GSK-3β inhibitors
-
Several analogues of isomeridianin G have been synthesized using palladium-catalyzed cross-coupling reactions of lithium triorganozincates as a key step. The latter have been prepared by deprotonative lithiation followed by transmetalation using ZnCl
- Seggio, Anne,Priem, Ghislaine,Chevallier, Floris,Mongin, Florence
-
experimental part
p. 3617 - 3632
(2010/03/05)
-
- Coupling of Organotin Reagents with Aryl, Acyl and Heteroaryl Halides Part Two: Synthesis of Thienylpyridine Derivatives
-
Coupling of organotin reagent Bu3SnAr (Ar = 2- or 3-pyridyl, or 2- or 3-thienyl) with appropriately halogenated heterocyclic in the presence of PdCl(CH2Ph)(PPh3)2 leads to the corresponding thienylpyridine derivative.Functionality is tolerated on the thiophene centre, but not in the case of the corresponding pyridine analogue.The compounds Bu3SnAr were prepared by a variety of methods, giving good yield of the tri-n-butylstannylated heterocycle.Other derivatives are prepared by direct reaction with the thienylpyridine nucleus.Examples of homo-coupling of the both organotin compounds and the aryl halide are also reported.
- Sosabowski, Michael H.,Powell, Paul
-
p. 201 - 219
(2007/10/03)
-
- SYNTHESIS OF 2-(2-THIENYL)PYRIDINE AND SOME OF ITS DERIVATIVES
-
2-(2-Thienyl)pyridine was obtained with a high yield from 2-thiophenecarbonitrile and acetylene at elevated pressure and temperature in the presence of η5-dicyclopentadienylcobalt (cobaltocene).The bromination, chlorination, nitration, carboxylation, and acetylation of 2-(2-thienyl)pyridine were studied.Oximation of 2-(5-acetyl-2-thienyl)pyridine in water-alcohol solution gave a mixture of 2-(5-methylcarbamoyl-2-thienyl)pyridine and syn-2-pyridine.
- Ivanov, A. P.,Levin, D. Z.,Promonenkov, V. K.,Mortikov, E. S.
-
p. 570 - 575
(2007/10/02)
-