The organocatalytic asymmetric allylic etherification reaction of Morita-Baylis-Hillman carbonates and silanols was reported for the first time. With modified cinchona alkaloid (DHQD)PYR as the catalyst, a series of aromatic, heterocyclic, or aliphatic Morita-Baylis-Hillman carbonates (25 examples) worked well with triphenylsilanol, affording the corresponding products in moderate to good yields (up to 98%), high regioselectivities (>20:1), and good enantioselectivities (up to 92%). When dimethylphenylsilanol was used as the nucleophile, the product was obtained in 60% yield and 87% ee.
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http://dx.doi.org/10.1021/acs.joc.6b01931 | DOI Listing |
Org Biomol Chem
January 2025
Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, School of Chemistry & Chemical Engineering, Tianjin University of Technology, Tianjin 300384, P. R. China.
As one of the main fragments in medical drugs, spirooxindole has received considerable attention from organic and medicinal chemists. In the past few decades, chemists have been searching for more straightforward and efficient methods to produce compounds containing a spirooxindole fragment. In this regard, isatin-derived Morita-Baylis-Hillman (MBH) carbonates have been widely used as versatile building blocks for the synthesis of spirooxindole structures.
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December 2024
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China.
A synergistic Pd/Cu catalyst system has been developed for stereodivergent transformation of Morita-Baylis-Hillman (MBH) carbonates and Schiff bases derived from simple amino acids to afford a series of optically active β-branched γ-methyleneglutamic acid derivatives with adjacent tertiary/tertiary and quaternary/tertiary stereocenters in high yields (up to 96 %) with excellent diastereo- and enantioselectivities (>20/1 dr and >99 % ee in most cases) under mild conditions. The use of SKP ligand is disclosed to be crucial for the success of the transformation, and in particular allowing the reaction to proceed at low catalyst loading (0.02 mol % for Pd and 0.
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December 2024
Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, Hubei 443002, China.
An unexpected phosphine-catalyzed controllable three-component domino reaction involving [1 + 2 + 2] annulation and [1 + 2 + 2]/[3 + 2] sequential annulation reaction of 2-arylmethylidene cyanoacetates/malononitriles with Morita-Baylis-Hillman (MBH) carbonates has been developed. A broad range of densely functionalized cyclopentanes and diquinanes bearing five or four consecutive stereogenic centers, including two all-carbon quaternary stereocenters, were smoothly acquired in moderate to excellent yields under mild reaction conditions from readily available materials. Moreover, this divergent transformation enables the simultaneous generation of three or four new C-C bonds and one or two carbocyclic rings in only one step.
View Article and Find Full Text PDFOrg Lett
December 2024
Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, College of Science, Southern University of Science and Technology Guangming Advanced Research Institute, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China.
Organocatalytic chemo- and enantioselective reactions of 2-amino-3-subsituted indoles have been achieved for the first time. Via asymmetric allylic alkylation of Morita-Baylis-Hillman carbonates, organocatalytic enantioselective dearomatization of 2-amino-3-subsituted indoles afforded an array of enantioenriched 3,3-disubstituted indolin-2-imines bearing a quaternary carbon stereocenter in 34-79% yields with 61-91% ee. With BocO as reaction partner, the organocatalytic enantioselective -acylation of 2-amino-3-subsituted indoles was established to furnish C-N axially chiral products in 22-98% yields with 73-92% ee.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Göteborg, Sweden.
The transition to a circular economy requires that we adapt currently used chemical processes to the structurally diverse and often highly oxygenated precursors that are accessible from biomass. In this review, we highlight different examples of carbon-carbon bond formation using aromatics derived from bio-based sources, reported during 2015-2024. Examples of sustainable biomass building blocks include heterocycles such as furfural and hydroxymethylfurfural, obtained from carbohydrates, as well as lignin-based aromatics such as vanillin and eugenol.
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