4902-32-3Relevant academic research and scientific papers
Aza-Matteson Reactions via Controlled Mono-and Double-Methylene Insertions into Nitrogen-Boron Bonds
Xie, Qiqiang,Dong, Guangbin
supporting information, p. 14422 - 14427 (2021/09/29)
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.
Ru-Catalyzed Switchable N-Hydroxyethylation and N-Acetonylation with Crude Glycerol
Xin, Zhuo,Jia, Le,Huang, Yuxing,Du, Chen-Xia,Li, Yuehui
, p. 2007 - 2011 (2020/03/19)
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.
Direct hydroxyethylation of amines by carbohydrates: Via ruthenium catalysis
Jia, Le,Makha, Mohamed,Du, Chen-Xia,Quan, Zheng-Jun,Wang, Xi-Cun,Li, Yuehui
supporting information, p. 3127 - 3132 (2019/06/18)
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.
Palladium-catalyzed intramolecular carbene insertion into C(sp3)-H bonds
Solé, Daniel,Mariani, Francesco,Bennasar, M.-Llu?sa,Fernández, Israel
, p. 6467 - 6470 (2016/06/01)
A palladium-catalyzed carbene insertion into C(sp3)-H bonds leading to pyrrolidines was developed. The coupling reaction can be catalyzed by both Pd0 and PdII, is regioselective, and shows a broad functional group tolerance. This reaction is the first example of palladium-catalyzed C(sp3)-C(sp3) bond assembly starting from diazocarbonyl compounds. DFT calculations revealed that this direct C(sp3)-H bond functionalization reaction involves an unprecedented concerted metalation-deprotonation step. Pd in action: Palladium has been used to catalyze the C(sp3)-H insertion of metal carbenoids derived from α-diazoesters to form pyrrolidines through intramolecular assembly of C(sp3)-C(sp3) bonds. A reaction mechanism involving a metalation-deprotonation step instead of the usual concerted but asynchronous process is proposed.
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
Hurst, Timothy E.,Gorman, Ryan M.,Drouhin, Pauline,Perry, Alexis,Taylor, Richard J. K.
supporting information, p. 14063 - 14073 (2016/02/18)
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.
