A new method for the direct conversion of 4-pentenylsulfonamides to 2-formylpyrrolidines and a 2-ketopyrrolidine has been developed. This transformation occurs via aerobic copper-catalyzed alkene aminooxygenation where molecular oxygen serves as both oxidant and oxygen source. The 2-formylpyrrolidines can further undergo oxidative carbon-carbon bond cleavage in situ upon addition of DABCO, providing 2-pyrrolidinones. These transformations have been demonstrated for a range of 4-pentenylsulfonamides. 4-Pentenylalcohols also undergo oxidative cyclization to form γ-lactones predominantly. The reaction is chemoselective, oxidizing one alkene in the presence of others, and is compatible with several functional groups. Application of these reactions to the formal syntheses of baclofen and (+)-monomorine was demonstrated.
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http://dx.doi.org/10.1021/jacs.7b05680 | DOI Listing |
Chem Sci
December 2024
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University Changchun Jilin 130012 China
The chemical recycling of polystyrene (PS) waste to value-added aromatic compounds is an attractive but formidable challenge due to the inertness of the C-C bonds in the polymer backbone. Here we develop a light-driven, copper-catalyzed protocol to achieve aerobic oxidation of various alkylarenes or real-life PS waste to benzoic acid and oxidized styrene oligomers. The resulting oligomers can be further transformed under heating conditions, thus achieving benzoic acid in up to 65% total yield through an integrated one-pot two-step procedure.
View Article and Find Full Text PDFChem Asian J
December 2024
Key Laboratory of Medicinal Chemistry for Natural Resource (Yunnan University), Ministry Education, School of Pharmacy, School of Chemical Science and Technology, Yunnan University, Kunming, 650091, P. R. China.
2,3'-Bisindoles with C-C linkages have attracted interest in medicinal chemistry, yet their synthesis is intricate with many steps. Notably, direct C-H/C-H cross-coupling of non-directed heteroaromatics remains challenging, often requiring precious metals and oxidants to enhance coupling efficiency. Herein, we present a copper-catalyzed C-H/C-H cross-coupling method for N-substituted indoles without directing groups, facilitated by molecular oxygen under gentle conditions.
View Article and Find Full Text PDFDespite the maturity of alkene 1,2-difunctionalization reactions involving C-N bond formation, a key limitation across aminofunctionalization methods is incompatibility with substrates bearing medicinally relevant N-heterocycles. Using a cooperative ligand-substrate catalyst activation strategy, we have developed an aerobic, copper-catalyzed alkene aminooxygenation method that exhibits broad tolerance for β,γ-unsaturated carbamates bearing aromatic azaheterocycle substitution. The synthetic potential of this methodology was demonstrated by engaging a densely-functionalized vonoprazan analogue and elaborating an amino oxygenated product to synthesize a heteroarylated analogue precursor of the FDA-approved antibiotic chloramphenicol.
View Article and Find Full Text PDFJ Org Chem
September 2024
College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000, China.
An aerobic copper-catalyzed oxysulfonylation of vinylarenes with sodium sulfinates is described. This protocol features mild reaction conditions, convenient operation, and broad substrate scope with respect to vinylarenes and sodium sulfinates. Notably, the protocol demonstrates excellent tolerance of functional groups such as chloro, bromo, ester, cyano, and nitro groups.
View Article and Find Full Text PDFChemSusChem
August 2024
Anhui Province Key Laboratory of Biomass Clean Energy, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, 230026, China.
2,5-diformylfuran (DFF) is a significant biomass-derived compound with diverse applications in novel furan-based materials, fragrances, fuel additives, and drug synthesis. A pivotal challenge in DFF synthesis was developing a method to produce DFF under mild conditions using sustainable feedstocks. In this study, an affordable 4-hydroxy-2,2,6,6-tetramethylpiperidine (TEMPOL)- assisted Cu(OAc) catalytic system for aerobic oxidation reaction of HMF to DFF in liquid sunlight methanol solvent was developed.
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