- N-heterocyclic carbene-Pd(II)-2-methyl-4,5-dihydrooxazole complex-catalyzed highly chemoselective mono-amination of dichlorobenzenes
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The palladium-catalyzed chemoselective mono-amination of dichlorobenzenes was reported in this paper. Under the suitable conditions, all reactions involving the three isomers of dichlorobenzenes with various secondary and primary amines in the presence of
- He, Qian-Wei,Lu, Jian-Mei,Shao, Li-Xiong,Sun, Kai-Xin,Zhou, Jin-Hui
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- Mixed er-NHC/phosphine Pd(ii) complexes and their catalytic activity in the Buchwald-Hartwig reaction under solvent-free conditions
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A series of novel (NHC)PdCl2-PR3 complexes were synthesized and fully characterized by 1H, 13C, 31P NMR and FT-IR spectroscopy. These complexes showed high catalytic activity toward solvent-free Buchwald-Hartwig amination. Both primary and secondary amines were efficiently utilized under the same reaction conditions. The solvent-free synthesis of valuable N-aryl carbazoles and similar N-heterocyclic systems was described.
- Ageshina, Alexandra A.,Sterligov, Grigorii K.,Rzhevskiy, Sergey A.,Topchiy, Maxim A.,Chesnokov, Gleb A.,Gribanov, Pavel S.,Nechaev, Mikhail S.,Asachenko, Andrey F.,Bermeshev, Maxim V.,Melnikova, Elizaveta K.
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supporting information
p. 3447 - 3452
(2019/04/30)
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- Transition metal-free amination of aryl halides-A simple and reliable method for the efficient and high-yielding synthesis of N-arylated amines
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A simple and reliable reaction protocol for the clean, fast, and high-yielding synthesis of various N-arylated amines derived from reactions of aryl halides with various (also sterically hindered) amines under transition metal-free reaction conditions is presented. Dioxane and KN(Si(CH3)3)2 were found to be the ideal solvent and base for this transformation. The conversion rates and yields observed are excellent and in the majority of the reactions performed significantly higher than that obtained in their catalyzed versions. Furthermore, the selective synthesis of 6-halopyridin-2-amines and asymmetric pyridine-2,6-diamines (derived from consecutive reactions of 2,6-dibromopyridine and 2,6-dichloropyridine, respectively, with different amines) is possible in almost quantitative yields (relative to 2,6-dihalopyridine) within very short reaction times. Purification of the 6-halopyridin-2-amine intermediates is not necessary, allowing the synthesis of pyridine-2,6-diamines in 'one-pot'. However, catalysts are in many cases not required to efficiently and selectively couple aryl halides with amines, making transition metal-free versions of the Buchwald-Hartwig reaction extremely attractive for the synthesis of N-arylated amines with substrates containing substituents on the aryl halide, which either promote regioselectivity and/or do not require regioselective aminations.
- Bolliger, Jeanne L.,Frech, Christian M.
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experimental part
p. 1180 - 1187
(2009/04/10)
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- Synthesis of 2,3-dihydroindoles, indoles, and anilines by transition metal-free amination of aryl chlorides
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Aliphatic and aromatic amines react with 2- and 3-chlorostyrene in the presence of potassium tert-butoxide to give N-substituted 2,3-dihydroindoles in good yields. The combination of this domino-amination protocol with a suitable dehydrogenation reaction gives access to pharmacologically interesting indoles in a one-pot procedure. Overall product yields of N-substituted indoles > 50% are obtained by this method starting from commercially available substrates. In addition to the intramolecular base-promoted amination of aromatic C-Cl, bonds, metal-free intermolecular aminations of aryl chlorides with primary and secondary amines are described. The use of potassium tert-butoxide as base allows the synthesis of various anilines in good to excellent yields. Due to the formation of aryne intermediates, either N-substituted anilines or meta-substituted anilines are produced with excellent selectivities.
- Beller,Breindl,Riermeier,Tillack
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p. 1403 - 1412
(2007/10/03)
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- On attempted oxidative cyclisation of isomeric N,N'-diphenylphenylenediamines and their N,N'-dimethyl derivatives by palladium(II) acetate and UV light
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The cyclisation of N,N'-diphenyl-o-, m- and p-phenylenediamines and their N,N'-dimethyl derivatives by palladium(II) acetate and UV light separately led to both bis-cyclisation, furnishing indolocarbazoles, and mono-cyclisations with cleavage as well as retention of one substituent, producing substituted carbazoles.
- Chakrabarty,Batabyal,Khasnobis
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p. 3651 - 3668
(2007/10/03)
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