Transition metal-catalyzed sp³ C–H activation and intramolecular C–N coupling to construct nitrogen heterocyclic scaffolds

Abstract

Nitrogen heterocycles are of great medicinal importance, and the construction of nitrogen heterocyclic scaffolds has been one of the focuses in synthetic organic chemistry.

Evaluation of polyphosphoric acid on the performance of polymer modified asphalt binders

“…In order to ensure and enhance the pavement quality, some admixtures were added into asphalt such as styrene–butadiene–styrene (SBS), crumb rubber (CR), and styrene butadiene rubber (SBR). Benefiting from the excellent performances, SBS is the most widely modifier for asphalt in China, and, SBR is often used to improve asphalt performance . Although SBS and SBR have achieved acceptable improvements for asphalt, there are still some problems that it is very hard to meet the demand for SBS and SBR modified asphalt applying in hot areas.…”

Functionalization of superparamagnetic Fe3O4@SiO2nanoparticles with a Cu(II) binuclear Schiff base complex as an efficient and reusable nanomagnetic catalyst forN‐arylation of α‐amino acids and nitrogen‐containing heterocycles with aryl halides

“…In the last decades, copper complexes (Cu(0), (I), or (II)) along with various ligands have been used for the C-N cross-coupling reactions (known as amination or N-arylation) of aryl halides with different type of amines, [1][2][3][4][5][6] because of the lower cost of copper salts and its application in the cross-coupling reactions as similar as Pd. [7,8] The first copper catalyzed C-N bond formation was developed by Ullman and Goldberg. [9,10] Various types of N-arylation have been reported in the literature that some examples come as follows: N-arylation of imidazoles, [11][12][13][14][15][16] Cu(I)-catalyzed N-arylation of indoles, [17] C-N coupling of aniline with terminal alkynes (synthesis of α-ketoamides), [18] copper-mediated C-N coupling reaction of azido compounds and aryl halides, [19] N-arylation of aryl halides with alkyl amine using CuBr catalyst which benefits from phosphoramidite as a ligand, [20] Cu(I)-catalyzed N-arylation of pyrazoles, [21] N-arylation of aryl iodide with hypervalent aryl siloxanes by Cu (OAc) 2 along with a ligand, [22] N-arylation of α-amino acids catalyzed by Cu(I), [23][24][25] cross-coupling reaction of aryl halides to aryl amines catalyzed by Cu 2 O in solution of ammonia, [26] N-alkynylation of amides catalyzed by Cu(I), [27] Cu(I)-amidation catalyzed of aryl halides, [28][29][30] Ullmann-type N-arylation of anilines, [31] Cu-catalyzed intramolecular adjacent C-N coupling (asymmetric synthesis of atropisomeric compounds), [32] Cu/N,N 0dibenzyloxalamide-catalyzed N-arylation of heteroanilines, [33] Cu-catalyzed N-arylation of sulfoximines, [34] Cu-catalyzed decarboxylative N-arylation...…”

Asymmetric Synthesis of Enantiopure Pyrrolidines by C(sp3)−H Amination of Hydrocarbons

“…C−H bonds are now considered as functional groups that allow the conception of efficient synthetic strategies with improved step‐ and atom‐economy [9] . This new paradigm in organic synthesis has found applications in heterocyclic chemistry with the use of new bond disconnections for the synthesis of nitrogen heterocycles [10] . With respect of pyrrolidines, three main strategies have been developed for their preparation (Scheme 1 a).…”

“…[9] This new paradigm in organic synthesis has found applications in heterocyclic chemistry with the use of new bond disconnections for the synthesis of nitrogen heterocycles. [10] With respect of pyrrolidines, three main strategies have been developed for their preparation (Scheme 1 a). Daugulis and Chen first reported the application of C À H activation reactions to the formation of pyrrolidines.…”