- Aza-Matteson Reactions via Controlled Mono-and Double-Methylene Insertions into Nitrogen-Boron Bonds
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Boron-homologation reactions represent an efficient and programmable approach to prepare alkylboronates, which are valuable and versatile synthetic intermediates. The typical boron-homologation reaction, also known as the Matteson reaction, involves formal carbenoid insertions into C-B bonds. Here we report the development of aza-Matteson reactions via carbenoid insertions into the N-B bonds of aminoboranes. By changing the leaving groups of the carbenoids and altering Lewis acid activators, selective mono- and double-methylene insertions can be realized to access various α- and β-boron-substituted tertiary amines, respectively, from common secondary amines. The derivatization of complex amine-containing bioactive molecules, diverse functionalization of the boronate products, and sequential insertions of different carbenoids have also been achieved.
- Xie, Qiqiang,Dong, Guangbin
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supporting information
p. 14422 - 14427
(2021/09/29)
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- Ru-Catalyzed Switchable N-Hydroxyethylation and N-Acetonylation with Crude Glycerol
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Highly efficient Ru-catalyzed selective C?C or C?O bond cleavage of polyols (e.g., crude glycerol) for N-hydroxyethylation or N-acetonylation of amines was achieved through the hydrogen-borrowing approach. A variety of amines were transformed to the desired amino alcohols/ketones in moderate-to-excellent yields, opening up new avenues for generation of oxygenated pharmaceuticals and fine chemicals from renewable raw materials. The use of new redox-active catalysts containing bisphosphine/thienylmethylamine ligands allows this hydrogen-borrowing system to be operated selectively under both basic and acidic conditions.
- Xin, Zhuo,Jia, Le,Huang, Yuxing,Du, Chen-Xia,Li, Yuehui
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p. 2007 - 2011
(2020/03/19)
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- Direct hydroxyethylation of amines by carbohydrates: Via ruthenium catalysis
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An efficient and halogen-free catalytic methodology for the synthesis of β-amino alcohols from aromatic amines and biomass-derived carbohydrates is demonstrated for the first time. The activation of C5/C6 sugars by a ruthenium catalyst selectively generates the C2 alkylating reagent glycolaldehyde. The transformation involves metal-catalyzed hydrogen borrowing for the reduction of the imine intermediate. A series of arylamines bearing various substituents were successfully transformed into the desired products in good to excellent yields.
- Jia, Le,Makha, Mohamed,Du, Chen-Xia,Quan, Zheng-Jun,Wang, Xi-Cun,Li, Yuehui
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supporting information
p. 3127 - 3132
(2019/06/18)
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- A Direct C-H/Ar-H Coupling Approach to Oxindoles, Thio-oxindoles, 3,4-Dihydro-1 H-quinolin-2-ones, and 1,2,3,4-Tetrahydroquinolines
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A copper(II)-catalysed approach to oxindoles, thio-oxindoles, 3,4-dihydro-1H-quinolin-2-ones, and 1,2,3,4-tetrahydroquinolines via formal C-H, Ar-H coupling is described. In a new variant, copper(II) 2-ethylhexanoate has been identified as an inexpensive and efficient catalyst for this transformation, which utilises atmospheric oxygen as the re-oxidant. Copper(II) 2-ethylhexanoate: The synthesis of oxindoles, thio-oxindoles, 3,4-dihydro-1H-quinolin-2-ones, and 1,2,3,4-tetrahydroquinolines from linear precursors by direct C-H, Ar-H coupling by using a single copper catalyst is reported (see scheme; DIPEA=diisopropylethylamine, EWG=electron-withdrawing group). The cyclisations are simple to perform, run open to the air, are moisture insensitive, and use an inexpensive catalyst.
- Hurst, Timothy E.,Gorman, Ryan M.,Drouhin, Pauline,Perry, Alexis,Taylor, Richard J. K.
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supporting information
p. 14063 - 14073
(2016/02/18)
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- Strategy for imidazotetrazine prodrugs with anticancer activity independent of MGMT and MMR
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The imidazotetrazine ring is an acid-stable precursor and prodrug of highly reactive alkyl diazonium ions. We have shown that this reactivity can be managed productively in an aqueous system for the generation of aziridinium ions with 96% efficiency. The
- Garelnabi, Elrashied A. E.,Pletsas, Dimitrios,Li, Li,Kiakos, Konstantinos,Karodia, Nazira,Hartley, John A.,Phillips, Roger M.,Wheelhouse, Richard T.
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supporting information
p. 965 - 968
(2013/02/23)
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- Copper(II) triflate catalyzed intermolecular aromatic substitution of N,N-disubstituted anilines with diazo esters
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The intermolecular aromatic substitution of N,N-disubstituted anilines with diazo esters is achieved under mild conditions in the presence of a catalytic amount of copper(II) triflate (up to 89 % yield). The scope and limitations regarding substrates, diazo esters, and ligands in this reaction are described. The intermolecular aromatic substitution of N,N-disubstituted anilines with diazo esters is shown to proceed under mild conditions in the presence of a catalytic amount of copper(II) triflate/ligand complex(up to 89 % yield). The scope and limitations regarding substrates, diazoesters, and ligands in this reaction are described. Copyright
- Tayama, Eiji,Yanaki, Tomoyo,Iwamoto, Hajime,Hasegawa, Eietsu
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supporting information; experimental part
p. 6719 - 6721
(2011/02/28)
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