The Ti(II) -mediated formation of cyclopropylamines from alkenes and amides, the Kulinkovich-de Meijere reaction, involves two carbon-carbon bond-forming steps. Strategic use of a tricyclic intermediate can arrest the process if the second step requires formation of a bridgehead double bond. Use of this Bredt's rule constraint results in the production of carbocyclic amino ketones, key alkaloid building blocks.
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http://dx.doi.org/10.1002/anie.201509983 | DOI Listing |
J Am Chem Soc
December 2024
State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
The homogeneous catalytic hydrogenation of benzo-fused heteroarenes generally provides partially hydrogenated products wherein the heteroaryl ring is preferentially reduced, such as quinoline hydrogenation, leading to 1,2,3,4-tetrahydroquinoline. Herein, we report a carbocycle-selective hydrogenation of fused -heteroarenes (quinoline, isoquinoline, quinoxaline, etc.) using the Ru complex of a chiral spiroketal-based diphosphine (SKP) as the catalyst, affording the corresponding 5,6,7,8-tetrahydro products in high chemoselectivities.
View Article and Find Full Text PDFBMC Med
October 2024
Division of Research, Kaiser Permanente Northern California, Pleasanton, CA, 94536, USA.
Molecules
September 2024
Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
Conformational freedom-restricted peptides, such as stapled peptides, play a crucial role in the advancement of functional peptide development. We synthesized stapled octapeptides using α-carbocyclic α,α-disubstituted α-amino acids, particularly 3-allyloxy-1-aminocyclopentane-1-carboxylic acid, as the crosslink motifs. The organocatalytic capabilities of the synthesized stapled peptides were assessed in an asymmetric nucleophilic epoxidation reaction because the catalytic activities are known to be proportional to α-helicity.
View Article and Find Full Text PDFJ Org Chem
September 2024
College of Science, Hebei Agricultural University, Baoding 071001, China.
Chiral manganese(I) complexes that contain carbocyclic-fused 8-amino-5,6,7,8-tetrahydroquinolinyl groups that are appended with distinct -R substituents have proven to be effective catalysts in the asymmetric transfer hydrogenation (ATH) of a wide range of ketones (48 examples). Notably, proved to be the most productive catalyst, allowing an outstanding turnover number of 8300 with catalyst loadings as low as 0.01 mol %.
View Article and Find Full Text PDFChem Rec
September 2024
Institute of Organic Chemistry, Stereochemistry Research Group, HUN-REN Research Center for Natural Sciences, H-1117, Budapest, Magyar tudósok krt. 2, Hungary.
2-Azabicyclo[2.2.1]hept-5-en-3-one (Vince lactam) is known to be a valuable building block in synthetic organic chemistry and drug research.
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