A synthetic approach that provides access to cis-cyclohepta-4,8-diene-fused pyrrolidines efficiently through Au(I) -catalyzed cycloisomerization of 1,6,8-dienyne carbonates and esters at a low catalyst loading of 2 mol % is reported. Starting carbonates and esters with a pendant alkyl group on the terminal alkenyl carbon center were found to favor tandem 1,2-acyloxy migration/cyclopropanation followed by Cope rearrangement of the resulting cis-3-azabicyclo[3.1.0]hexane intermediate. On the other hand, substrates containing a terminal diene or starting materials in which the distal alkene moiety bears a phenyl substituent were observed to undergo competitive but reversible 1,3-acyloxy migration prior to the nitrogen-containing bicyclic ring formation. The delineated reaction mechanism also provides experimental evidence for the reversible interconversion between the oft-proposed organogold intermediates obtained in this step of the tandem process.
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http://dx.doi.org/10.1002/chem.201402500 | DOI Listing |
Adv Sci (Weinh)
January 2025
School of Low-Carbon Energy and Power Engineering, China University of Mining and Technology, NO. 1 DAXUE ROAD, Xuzhou, Jiangsu, 221116, China.
With the increasing demand for thermal management, phase change materials (PCMs) have garnered widespread attention due to their unique advantages in energy storage and temperature regulation. However, traditional PCMs present challenges in modification, with commonly used physical methods facing stability and compatibility issues. This study introduces a simple and effective chemical method by synthesizing seven ester-based PCMs through chemical reactions involving lauric acid (LA) and seven different alcohols.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Jain University - Ramanagara Campus, Centre for Nano and Material Sciences, Jakkasandra Post Kanakapura Taluk, Ramanagara-562112, Bangalore, 562112, Bangalore, INDIA.
The development of a metallic copper-based catalyst system remains a significant challenge. Herein, we report the synthesis of highly stable, active, and reusable Cu0 catalyst for the carboboration of alkynes using carbon electrophiles and bis(pinacolato)diboron (B2pin2) as chemical feedstocks to afford di- and trisubstituted vinylboronate esters in a regio- and stereoselective manner with appreciable turnover number (TON) of up to 2535 under mild reaction conditions. This three-component coupling reaction works well with a variety of substituted electrophiles and alkynes with broad functional group tolerance.
View Article and Find Full Text PDFChem Sci
January 2025
Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology (SCUT) Guangzhou 510640 China.
Radical-mediated dearomatization strategies offer a blueprint for building value-added and synthetically valuable three-dimensional skeletons from readily available aromatic starting materials. Herein, we report a novel strategy by leveraging benzene-linked O-oxime esters as triply functionalized precursors to form two distinct persistent radicals under a chemodivergent pathway. These radicals then couple with a cyclohexadienyl radical for either carboamination or carbo-aminoalkylation.
View Article and Find Full Text PDFChemSusChem
January 2025
VITO NV, Match Unit, BELGIUM.
The growing pursuit of carbon circularity in material fabrication has led to the increased use of recycled and biobased resources, especially in epoxy resin systems. Fossil-based bisphenols are being replaced with recycled bisphenol A (r-BPA) and lignin derivatives, both derived from previous processes. In this study, r-BPA was chemically recycled from end-of-life televisions, then converted into r-DGEBA and r-DAGBA through glycidylation and acrylic acid ring-opening.
View Article and Find Full Text PDFTannase, as a type of tannin-degrading enzyme, can catalyze the hydrolysis of ester and depside bonds in gallotannins, thereby releasing gallic acid and glucose. Based on this reaction mechanism, Tannase can effectively improve the problems of bitter taste, weak aroma, and tea cheese in tea infusion, and is therefore widely used in the tea industry. However, due to high production costs, difficulties in purification and recovery, and insufficient understanding of Tannase properties, the large-scale application of Tannase is severely limited.
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