Acyclic nucleoside phosphonates have been prepared in a straightforward manner and in high yields by an enantioselective palladium-catalyzed allylic substitution involving nucleic bases as nucleophiles followed by cross-metathesis reaction with diethyl allylphosphonate.
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http://dx.doi.org/10.1039/c7ob01478c | DOI Listing |
Org Lett
December 2024
School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China.
An efficient palladium-catalyzed -allylic alkylation of pyrazoles and unactivated vinylcyclopropanes is demonstrated, affording various -alkyl pyrazoles in ≤99% yield. This protocol displays high atom economy, a broad range of substrates, and excellent regioselectivity and stereoselectivity. Late-stage modification of bioactive molecules, scaled-up reaction, and divergent derivatization documented the practicability of this methodology.
View Article and Find Full Text PDFOrg Lett
December 2024
Institut für Chemie, Universität Oldenburg, D-26129 Oldenburg, Germany.
Optically active spirocycles were prepared in a sequence of two palladium-catalyzed reactions. In the first step, racemic α-(-iodophenyl)-β-oxo allyl esters were submitted to the palladium-catalyzed decarboxylative asymmetric allylic alkylation reaction, furnishing the α-allylated products with a quaternary stereocenter with good yields and enantioselectivities. Subsequently, these intermediate products were converted in a Heck reaction yielding the spirocyclic structures as a mixture of - and -cyclic regioisomers.
View Article and Find Full Text PDFNat 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 PDFAngew Chem Int Ed Engl
November 2024
Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, MP, India.
We report herein a directing group-controlled, palladium-catalyzed, regio-, stereo-, and enantiospecific anti-carboxylation of unactivated, internal allenes enabled via the synergistic interplay of a rationally designed bidentate directing group, palladium catalyst, and a multifunctional acetate ligand. The corresponding trans allyl ester was obtained in excellent yields with exclusive δ-regioselectivity and anti-carboxypalladation stereocontrol. The acetate ligand of the palladium catalyst controls the regio-, stereo- and enantioselectivity in the desired transformation.
View Article and Find Full Text PDFMolecules
October 2024
Laboratory of Molecular Chemistry, Faculty of Sciences Semlalia, Cadi Ayyad University, B.P. 2390, Marrakech 40001, Morocco.
Allylic oxygenated derivatives of himachalenes are highly valued molecules due to their potential applications in perfumery, cosmetics, and pharmaceuticals. Previous attempts at catalyzed allylic oxidation of himachalenes led to the formation of a very stable η-allyl palladium complex, preventing any further reaction development. Herein, we present the first successful palladium-catalyzed synthesis of a novel allylic acetoxylated derivative of himachalenes.
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