Despite the relatively low reactivities of urea and thiourea functional groups towards nucleophilic attack, we have found conditions in which they are useful substrates in Friedel-Crafts reactions. The Brønsted superacid, triflic acid, promotes these reactions and a mechanism is proposed involving dicationic, superelectrophilic intermediates.
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http://dx.doi.org/10.1039/c2cc34062c | DOI Listing |
Sci Rep
January 2025
Faculty of Chemistry, University of Guilan, P. O. Box: 41335-1914, Rasht, Iran.
The catalytic efficiency of sulfonated polystyrene foam waste (SPS) and sulfonated gamma alumina (SGA) in Friedel-Crafts type reactions was compared. All of the materials were studied using the state-of-the-art characterization techniques. SPS was found to carry a higher load of -SOH functional groups (1.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
State Key Laboratory of Applied Organic Chemistry (SKLAOC), Key Laboratory of Special Function Materials and Structure Design (MOE), College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, China.
Angew Chem Int Ed Engl
October 2024
Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
Sulfur functional groups are ubiquitous in molecules used in the pharmaceutical and agrochemical industries, and within these collections sulfones hold a prominent position. The double aza-analogues of sulfones, sulfondiimines, offer significant potential in discovery chemistry but to date their applications have been limited by the lack of convenient synthetic routes. The existing methods mainly rely on imination of low-valent-sulfur intermediates, or the combination of pre-formed organometallic reagents and electrophilic S(VI)-functionalities.
View Article and Find Full Text PDFJ Org Chem
November 2024
Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798-7348, United States.
Chlorosulfonyl isocyanate (CSI) is a complex reagent capable of facilitating numerous synthetic transformations, including lactam/lactone formation, sulfonylation, Friedel-Crafts-type acylations, and cycloadditions. Annulation reactions to form nitrogen-, oxygen-, and sulfur-bearing heterocycles have been observed with CSI; however, the application of CSI toward the generation of fused cyclic ketone ring systems has not been previously reported. A serendipitous discovery of the pertinence of CSI occurred during a structure-activity relationship campaign around our established lead benzosuberene-based molecule that functions as a potent inhibitor of tubulin polymerization.
View Article and Find Full Text PDFHeliyon
August 2024
Chemistry Division, School Of Advanced Science, VIT Chennai, Chennai, 600127, Tamil Nadu, India.
An efficient metal-free, triflic acid-promoted intramolecular Friedel-Crafts-type carbocyclization of alkenylated biphenyl derivatives is discussed. This method provides an elegant route for the construction of 9,10-dihydrophenanthrenes of biological significance in good to excellent yields. The carbocyclization reaction is likely to proceeds via activation of terminal C[bond, double bond]C bond of alkenylated biphenyl derivatives followed by subsequent aromatic electrophilic substitution to give desired carbocyclic products.
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