A series of 2-dialkylphosphino-2'-alkoxy-1,1'-binaphthyl ligands (6a-c and 8a-c) have been prepared conveniently by a lithium-initiated ring-opening reaction of dinaphthofuran, followed by selective phosphorylation. These compounds displayed a remarkable air and moisture stability, both in solid form and in solution. Application of these phosphine ligands in palladium-catalyzed C-N bond forming reactions revealed the crucial roles of the steric bulk of the substituents on the phosphorus atom governing the catalytic activity. Specifically, 2-di-tert-butylphosphino-2'-isopropoxy-1,1'-binaphthyl (8b) proved to be the most effective for the aminations of aryl halides with primary amines, while the less bulky 2-dicyclohexyl-2'-methoxy-1,1'-binaphthyl (6a) was more effective for the aminations with secondary amines. The steric and electronic effects of the ligands were analyzed to account for these observations.
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http://dx.doi.org/10.1021/jo060945k | DOI Listing |
Chem Commun (Camb)
December 2024
College of Chemistry and Pharmaceutical Engineering, Nanyang Normal University, Nanyang 473061, China.
A palladium-catalyzed divergent reaction of primary benzamides using norbornene (NBE) derivatives as a controlled switch is reported. When NBE is used as a mediator, indanones are synthesized with moderate to good yields a Catellani reaction that involves sequential -C-H alkylation and -C-N bond cleavage annulation of primary benzamides. Employing norbornadiene (NBD) instead of NBE enables the assembly of -alkylamines by an intermolecular hydroamination reaction.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, India.
Palladium-catalyzed directed site-selective C(sp)-H alkylation of 8-methylquinolines has been accomplished using aziridine as the alkylating source a sequential C-H and C-N bond activation process. The site selectivity, functional group tolerance and possible late-stage modifications are important practical features of this reaction.
View Article and Find Full Text PDFChemSusChem
October 2024
CNRS, Université Lyon 1, 43 Bd du 11 novembre 1918 69622 Villeurbanne Cedex - Fr, Bat. Lederer (4ème étage), 69622, Villeurbanne, FRANCE.
In this study, we demonstrate that phosphinoacridines are efficient bidentate ligands for palladium-catalyzed carboxylative C-N coupling reactions under blue LED irradiation. This method facilitates the direct synthesis of arylcarbamates using a range of non-activated aryl halides, such as iodides and bromides, with various amines under atmospheric pressure of CO2. The optimized conditions exhibit high tolerance to sensitive functional groups, resulting in very good to excellent yields of the desired products.
View Article and Find Full Text PDFAcc Chem Res
October 2024
School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore.
ConspectusSynergy between the teaching and research activities of a University should be a source of new ideas, each informing the other. A classroom discussion gave rise to our concept of using hydroxylamines as a form of "tethered nitrogen" for alkaloid synthesis. The "tether" temporarily connects a nucleophilic nitrogen atom to the substrate, rendering an intermolecular reaction intramolecular, thus providing stereo- and regiochemical control for C-N bond formation.
View Article and Find Full Text PDFJ Org Chem
September 2024
College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China.
Palladium-catalyzed Suzuki-Miyaura cross-coupling is an efficient approach for C-C bond construction. Here we report a deaminative Suzuki-Miyaura reaction to achieve chemo- and regioselectivity in the cross-coupling of nonactivated propargylamines with boronic acids, in which methyl propiolate is introduced to promote the cleavage of the C-N bond to form the C-C bond. This method features a wide range of substrates, good functional group tolerance, and ease of operation, providing an alternative approach to accessing valuable propargylated aromatic compounds.
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