A series of bifunctional asymmetric phase-transfer catalysts containing novel fluorine-containing urea groups derived from cinchona alkaloids have been synthesized and successfully applied in the asymmetric intramolecular Mannich reaction. The 4-azaindoline products bearing multiple substrates were obtained in excellent yield (90-99%), with high enantioselectivity (up to 95%) and diastereoselectivity (up to >99:1).
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http://dx.doi.org/10.1021/acs.joc.9b03025 | DOI Listing |
J Mol Graph Model
January 2025
School of Science, Walailak University, Nakhon Si Thammarat, 80160, Thailand. Electronic address:
The crucial role of the amine functional group at the Mannich bridge of polybenzoxazines (PBZs) has been reported to be responsible for their hydrogen-bonded network structures. However, they have not been thoroughly studied in an aqueous solution and at the atomistic level. In this study, molecular dynamics simulations were applied to investigate the formation of hydrogen bond interactions of PBZs prepared from bisphenol A/methylamine (m-PBZ), bisphenol A/aniline-based (a-PBZ), and bisphenol A/2-(methylamino)ethylamine (e-PBZ).
View Article and Find Full Text PDFJ Org Chem
September 2024
Key Lab of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P. R. China.
Density functional theory calculations were conducted to refine our understanding at the molecular level of the synthesis of fused 1,2-dihydroquinolines through Rh- and acid-catalyzed skeleton-reorganizing coupling reactions of cycloheptatriene with amines. The results reveal that the reaction progresses via cascade catalysis, consisting of consecutive steps of Rh-catalyzed intermolecular coupling involving two Rh-Rh-Rh transformations with a maximum energy barrier of 27.1 kcal/mol, followed by acid-catalyzed intramolecular skeleton reorganization with a peak energy barrier of 23.
View Article and Find Full Text PDFMol Divers
September 2024
Department of Chemistry, SRM Institute of Science & Technology, Delhi-NCR Campus, Modinagar, Ghaziabad, 201204, India.
Arborisidine and Arbornamine are two monoterpenoid indole alkaloids that were isolated from the Malayan Kopsia arborea plant. This review provides valuable information about the total and formal syntheses of these alkaloids. The synthesis strategies discussed in this review, such as Pictet-Spengler cyclization, chemo- and stereoselective oxidative cyclization, Michael/Mannich cascade process, and intramolecular N-alkylation, can be useful for developing new methods to synthesize these and other similar compounds.
View Article and Find Full Text PDFOrg Lett
August 2024
Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan.
An enantioselective addition reaction of alkynyl esters with imines was developed under asymmetric autotandem catalysis with a chiral Brønsted base. A chiral bis(guanidino)iminophosphorane organosuperbase, which has much higher basicity than that of conventional chiral organic bases, efficiently promoted both the intramolecular cyclization for the construction of a benzofuran ring or a benzothiophene ring and the sequential enantioselective direct Mannich-type reaction of diarylmethane derivatives, affording enantio-enriched diarylalkane derivatives that are otherwise difficult to access.
View Article and Find Full Text PDFArch Pharm (Weinheim)
September 2024
Institut für Pharmazeutische und Medizinische Chemie, Universität Münster, Münster, Germany.
Cyclopenta[g]quinolones of type 4 were designed with the aim to bioisosterically replace the phenol of potent GluN2B ligands such as ifenprodil and Ro 25-6981 by the quinolone system and to restrict the conformational flexibility of the aminopropanol substructure in a cyclopentane system. The designed ligands were synthesized in an eight-step sequence starting with terephthalaldehyde (5). Key steps pf the synthesis were the intramolecular Friedel-Crafts acylation of propionic acids 10 to yield the cyclopenta[g]quinolinediones 11 and the Mannich reaction of diketone 11a followed by conjugate addition at the α,β-unsaturated ketone 12a.
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