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2-O-Acyl protected-d-ribo-3-uloses reacted with [(ethoxycarbonyl)methylene]triphenylphosphorane in acetonitrile to afford regio- and stereoselectively 2-(Z)-alkenes in 10-60 min under microwave irradiation. This domino reaction is proposed to proceed via tautomerization of 3-ulose to enol, acyl migration, tautomerization to the 3-O-acyl-2-ulose, and Wittig reaction. Alternatively, in chloroform, regioselective 3-olefination of 2-O-pivaloyl-3-uloses gave (E)-alkenes, key precursors for the miharamycins' bicyclic sugar moiety.
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http://dx.doi.org/10.1021/acs.orglett.5b02849 | DOI Listing |
Chem Commun (Camb)
September 2025
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 additive-controlled chemodivergent multi-component domino reaction of salicylaldehydes with MBH carbonates has been skillfully developed. Interestingly, acid additives regulate the reaction to form functionalized cyclohexenes or natural coumarin derivatives. Notably, the coumarins were produced a novel phosphine-mediated α-umpolung/Wittig olefination/cycloaddition/lactonization/elimination cascade.
View Article and Find Full Text PDFFood Chem
August 2025
Food Chemistry, School of Mathematics and Natural Sciences, University of Wuppertal, Gaussstrasse 20, 42119 Wuppertal, Germany. Electronic address:
Densipolic acid (DA, 12-OH-9Z,12Z-octadecadienoic acid) has been identified in Paysonia species, and recent analyses have indicated the presence of DA and its trans-isomer (tDA, 12-OH-9E,12Z-octadecadienoic acid) in edible oils. This study describes the first synthetic approach for DA and tDA using a Wittig reaction and a Julia-Kocienski olefination as stereoselective olefination reactions. A library of 22 vegetable oils was analyzed by LC-MS using these two products as standards.
View Article and Find Full Text PDFOrg Lett
August 2025
Department of Chemistry, National Taiwan Normal University, 88, Sec. 4, Tingchow Road, Taipei 11677, Taiwan, R.O.C.
We disclose phosphine-mediated double annulation via a one-pot reaction for the construction of functionalized pyrrolofuranthridones. This one-pot protocol involves a Morita-Baylis-Hillman (MBH)-type/O-acylation/Wittig reaction sequence. Broad functional group tolerance is displayed, and a range of pyrrolofuranthridones are obtained in good to high yields.
View Article and Find Full Text PDFACS Omega
August 2025
Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, São Paulo, SP 05508-000, Brazil.
The phenolic sesquiterpene (±)-jungianol, originally isolated from (family ), has previously been targeted through various synthetic approaches. However, none of these methods have successfully produced (±)-jungianol as the major product, largely due to difficulties in synthesizing -1,3-substituted indane frameworks. Herein, we present an annulative strategy for the total synthesis of (±)-jungianol, emphasizing several key transformations, including olefination via Wittig and Grignard reactions, hydrogenation, iodination, cross-coupling reactions, oxidation, acetylation, and hydrogenolysis of the acetylated product.
View Article and Find Full Text PDFJ Org Chem
August 2025
Área de Química Orgánica, Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Pza. Misael Bañuelos s/n, 09001 Burgos, Spain.
A thermally controlled rare chemodivergent mechanistic trifurcation has been found through experimental and computational efforts. Notably, one of the available paths in this three-way mechanism allows for an unprecedented dearomatization reactivity of non-activated 2-arylphenyl benzyl ethers under very mild thermal conditions after Csp-H bond functionalization through α-lithiation, bringing easy access to regioselectively functionalized dearomatized benzochromene scaffolds via anionic dearomatization enabled by carbolithiation of a non-activated aromatic ring. A [1,2]-Wittig rearrangement and a benzyl migration reaction complete the available product alternatives.
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