An efficient strategy for preventing the β-hydride elimination of alkylpalladium species by ligation of the palladium with adjacent amino-group was developed, which enabled a novel palladium-catalyzed ring-closing aminoalkylative amination of unactivated aminoenynes. The reaction is amenable to aminals, as well as aliphatic aldehydes with secondary amines, which provides straightforward access to structurally diverse exocyclic allenic amines bearing 5 to 12-membered N-heterocycles. With chiral phosphoramidite-ligated palladium complex as the catalyst, an enantioselective variant was achieved with up to 93 % ee. Simultaneously, synthetic transformations of the chiral products were also conducted to afford structurally unique spirodiamines including one pharmaceutically active molecule via axial-to-central chirality transfer.
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http://dx.doi.org/10.1002/anie.202215325 | DOI Listing |
Nat Commun
December 2024
Key Laboratory of Precision and Intelligent Chemistry and Department of Chemistry, University of Science and Technology of China, 230026, Hefei, P. R. China.
Even though tuning electronic effect of chiral ligands has proven to be a promising method for designing efficient catalysts, the potential to achieve highly selective reactions by this strategy remains largely unexplored. Here, we report a palladium-catalyzed enantioselective ring-closing aminoalkylative amination of aminoenynes enabled by rationally tuning the remote electronic property of 1,1'-binaphthol-derived phosphoramidites. With a tailored 6,6'-CN-substituted 1,1'-binaphthol-derived phosphoramidite as a ligand, a broad range of aromatic amines are compatible with this reaction, allowing the efficient synthesis of a series of enantioenriched exocyclic allenylamines bearing saturated N-heterocycles with up to >99% enantiomeric excess.
View Article and Find Full Text PDFAdv Carbohydr Chem Biochem
November 2024
Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts, USA.
The various methods for the de novo asymmetric synthesis of the pyranose sugars are surveyed in this update of the 2013 Advances in Carbohydrate Chemistry and Biochemistry review. The survey begins with a general overview of the various de novo approaches to carbohydrates and defines the use of asymmetric catalysis for the de novo asymmetric synthesis of pyranoses. Next the application to pyranose-containing oligosaccharides is introduced via the use of a palladium-mediated glycosylation.
View Article and Find Full Text PDFJ Am Chem Soc
August 2024
Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas 75390, United States.
We describe the first total synthesis of the unusual cyclopropane-containing indole alkaloid (-)-rauvomine B via a strategy centered upon intramolecular cyclopropanation of a tetracyclic -sulfonyltriazole. Preparation of this precursor evolved through two generations of synthesis, with the ultimately successful route involving a palladium-catalyzed stereospecific allylic amination, a -selective Pictet-Spengler reaction, and ring-closing metathesis as important bond-forming reactions. The key cyclopropanation step was found to be highly dependent on the structure and conformational strain of the indoloquinolizidine -sulfonyltriazole precursor, the origins of which are explored computationally through DFT studies.
View Article and Find Full Text PDFJ Org Chem
January 2024
János Szentágothai Research Centre, University of Pécs, Ifjúság u. 20., Pécs H-7624, Hungary.
Palladium-catalyzed aminocarbonylation of 3-iodochromone was studied in the presence of primary and secondary amines using atmospheric pressure of carbon monoxide as a carbonyl source. This procedure successfully provided a library of chromone-3-carboxamides and 3-substituted chroman-2,4-diones in 40 to 92% isolated yields. The reaction proceeded via highly chemoselective aminocarbonylation (up to 100%) in the presence of secondary amines by using monodentate or bidentate phosphine ligands.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2023
Key Laboratory of Precision and Intelligent Chemistry and Department of Chemistry, University of Science and Technology of China, Hefei, 230026, P. R. China.
A novel and efficient palladium-catalyzed regioselective and stereodivergent ring-closing reaction of aminoenynes with aldehydes and boronic acids or hydrosilane is developed. This three-component reaction allows for the modular synthesis of a series of exocyclic 1,3-dienes bearing 5- to 8-membered saturated N-heterocycles. The reactions utilize a simple Pd-catalyst and work with broad range of aminoenynes, aldehydes and organometallic reagents under mild reaction conditions.
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