A facile access to optically active cyclic ureas was developed through palladium-catalyzed asymmetric hydrogenation of pyrimidines containing tautomeric hydroxy group with up to 99 % ee. Mechanistic studies indicated that reaction pathway proceed through hydrogenation of C=N of the oxo tautomer pyrimidin-2(1H)-one, acid-catalyzed isomerization of enamine-imine, and hydrogenation of imine pathway. In addition, the chiral cyclic ureas are readily converted into useful chiral 1,3-diamine and thiourea derivatives without loss of optical purity.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/anie.201801485 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Sulfur and Oxygen Transfer Reactions with Simultaneous NHC-Coordination from Cyclic Thioureas and Ureas to a Stable Silylene.
Chemistry
December 2024
Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai, 980-8578, Japan.
Reactions of cyclic thioureas (1,3,4,5-tetramethylimidazol-2-thione and 1,3-dimethylimidazolidin-2-thione) and ureas (1,3,4,5-tetramethylimidazol-2-one and 1,3-dimethylimidazolidin-2-one) with an isolable dialkylsilylene were examined. In these reactions, cyclic thioureas served as sulfur and NHC (N-heterocyclic carbene) sources, and the corresponding silanethione and NHC-derived products formed via silanethione-NHC complexes. Reactions of cyclic ureas with the silylene afforded a new NHC and an isolable azomethine ylide.
View Article and Find Full Text PDFElectrosynthesis of Cyclic Isoureas and Ureas Through Contiguous Heterofunctionalizations.
J Org Chem
August 2024
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India.
An efficient synthetic protocol for the selenylated cyclic isoureas was developed using electrochemical activation of diselenides. This sustainable approach permitted transition metal and chemical oxidant-free difunctionalization of olefins and overall access to distinct 1,2,3 triheterofunctionalized carbon skeletons. Excellent functional group tolerance was noticed, allowing the synthesis of a series of cyclic isourea derivatives.
View Article and Find Full Text PDFSynergetic binary organocatalyzed ring opening polymerization for the precision synthesis of polysiloxanes.
Commun Chem
March 2024
Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
Organocatalytic ring-opening polymerization (ROP) is a versatile method for synthesizing well-defined polymers with controlled molecular weights, dispersities, and nonlinear macromolecular architectures. Despite spectacular advances in organocatalytic ROP, precision synthesis of polysiloxanes remains challenging due to the mismatch in polarity between highly polar initiators and nonpolar monomers and polymers and the difficulty in suppressing the formation of scrambling products via transetherification reactions during ROP of cyclic siloxanes. Here, we describe a binary organocatalytic ROP (BOROP) of hexamethylcyclotrisiloxane (D3) employing organic bases as catalysts and (thio)ureas as cocatalysts.
View Article and Find Full Text PDFThree-Component Reaction for the Synthesis of Spiro-Heterocycles from Isatins, Substituted Ureas, and Cyclic Ketones.
J Org Chem
March 2024
Jiangsu Engineering Research Center of Biological Data Mining and Healthcare Transformation, Xuzhou Medical University, Xuzhou 221004, Jiangsu, PR China.
We reported an efficient three-component reaction to access new spiro heterocycles through the annulation reactions of isatins, substituted ureas, and under normal laboratory conditions, which is another example of isatins being used to build spiro compounds by the ring-opening and recyclization processes. The wide range of substrates, simple operation, normal experimental conditions, and high yields make the approach of high practical value.
View Article and Find Full Text PDFPalladium-catalyzed ligand-regulated divergent synthesis of pyrrole[2,3-]indoles and ureas from 2-ethynylanilines and isocyanides.
Chem Commun (Camb)
March 2024
Key Laboratory of Functional Molecular Engineering of Guangdong Province, State Key Laboratory of Luminescent Materials and Devices, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China.
Herein, a palladium-catalyzed and ligand-controlled protocol for the divergent synthesis of pyrrole[2,3-]indole and urea derivatives has been described. Pyrrole[2,3-]indoles ("cyclization on" products) tandem cyclization of -alkynylanilines with isocyanides in the absence of a ligand and ureas ("cyclization off" products) oxidative amination of anilines with isocyanides in the presence of a ligand were obtained both in moderate to good yields with high selectivity. In this chemistry, cyclic and acyclic products were easily accessed with the same starting materials under the regulation of the ligand.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!