An N-heterocyclic carbene (NHC)-catalyzed highly diastereo- and enantioselective formal [3+2] reaction of o-hydroxy aromatic aldimines and cinnamaldehydes for the preparation of enantioenriched trans-γ-lactams was developed. An internal hydrogen bond between the o-hydroxy and the imine function was crucial for the reactivity and chemical selectivity. Trans-γ-lactam 3 d was easily oxidized to multifunctional 1,4-benzoquinone 8, which could further be transformed to biaryl 9 in the presence of a phosphoric acid. Finally, preliminary results for a kinetic resolution of (±)-trans-γ-lactam 3 d under asymmetric NHC catalysis are reported.
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http://dx.doi.org/10.1002/chem.201703263 | DOI Listing |
Molecules
January 2025
Laboratoire de Chimie Agro-Industrielle (LCA), Université de Toulouse, INRAE, 4 allée Emile Monso, 31030 Toulouse, France.
In organic synthesis, the solvent is the chemical compound that represents the largest proportion of the process. However, conventional solvents are often toxic and dangerous for the environment, and an interesting alternative is to replace them by water. In this context, catalyst surfactants allow both organic reagents in water to be solubilized and organic reactions to be catalyzed.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.
Chiral medium-sized rings, albeit displaying attractive properties for drug development, suffer from numerous synthetic challenges due to difficult cyclization steps that must take place to form these unusually strained, atropisomeric rings from sterically crowded precursors. In fact, catalytic enantioselective cyclization methods for the formation of chiral seven-membered rings are unknown, and the corresponding eight-membered variants are also sparse. In this work, we present a substrate preorganization-based, enantioselective, organocatalytic strategy to construct seven- and eight-membered rings featuring chirality that is intrinsic to the ring in the absence of singular stereogenic atoms or single bond axes of chirality.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
Axially chiral -VQMs have been extensively investigated as key intermediates to approach miscellaneous chiral structures. By sharp contrast, their structural isomers -VQMs have not been previously documented. The major reason, which results in the significant delay, may ascribe to the inherent challenges in the enantioselective activation of alkynes in a remote manner.
View Article and Find Full Text PDFChemSusChem
January 2025
Universidad de Antioquia Facultad de Ciencias Exactas y Naturales, Instituto de Química, Calle 70 No 52-21, Medellín, NA, Medellín, COLOMBIA.
In recent years, mechanosynthesis of peptides through either chemical or enzymatic routes has been accomplished. In part, this advancement has been driven due to the organocatalytic properties of peptide-based biomaterials. In this work, we report the merging of chemical and enzymatic protocols under mechanochemical conditions to synthesize peptide materials based on L-proline and L-phenylalanine.
View Article and Find Full Text PDFBeilstein J Org Chem
January 2025
Department of Organic Chemistry, Faculty of Natural Science, Comenius University Bratislava, Mlynská dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia.
Axial chirality is present in a variety of naturally occurring compounds, and is becoming increasingly relevant also in medicine. Many axially chiral compounds are important as catalysts in asymmetric catalysis or have chiroptical properties. This review overviews recent progress in the synthesis of axially chiral compounds via asymmetric organocatalysis.
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