4161-60-8Relevant articles and documents
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Tanabe,T.
, p. 1482 - 1488 (1973)
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Tsuji-Wacker-Type Oxidation beyond Methyl Ketones: Reacting Unprotected Carbohydrate-Based Terminal Olefins through the "uemura System" to Hemiketals and α,β-Unsaturated Diketones
Runeberg, Patrik A.,Eklund, Patrik C.
supporting information, p. 8145 - 8148 (2019/10/11)
Aerobic Pd(AcO)2/pyridine-catalyzed oxidation of unprotected carbohydrate-based terminal alkenes was studied. In accordance with previous reports, the initial reaction step gave methyl ketones. However, our substrates partially gave subsequent α,β-water elimination and alcohol oxidation to α,β-unsaturated 2,5-diketones. Upon increasing the pressure of O2, the reaction was shifted toward formation of α,β-epoxy-2-ketones. The reactions were stereoselective and gave up to quantitative conversions. However, isolated yields were substantially lower because of the complexity of the product mixtures.
Base-Free Transfer Hydrogenation of Ketones Using Cp?Ir(pyridinesulfonamide)Cl Precatalysts
Ruff, Andrew,Kirby, Christopher,Chan, Benny C.,O'Connor, Abby R.
, p. 327 - 335 (2016/02/19)
N-(2-(Pyridin-2-yl)ethyl)benzenesulfonamide derivatives and 1,1,1-trifluoro-N-(2-(pyridin-2-yl)ethyl)methanesulfonamide (1-4), along with three-legged piano stool Cp?IrIIICl complexes (5-11) (Cp? = pentamethylcyclopentadienyl) bearing pyridinesulfonamide ligands with varying electronic parameters, were synthesized. These ligands and air-stable complexes were characterized by 1H and 13C{1H} NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Precatalysts, 5-11, were assessed for transfer hydrogenation of aryl, diaryl, dialkyl, linear, cycloaliphatic, and α,β-unsaturated ketones, diones, β-ketoesters, and a biomass-derived substrate with 2-propanol, using 1 mol % precatalyst. Catalysis was also efficient using a 0.1 mol % loading. Remarkably, all catalysis experiments can be conducted in air without dried and degassed substrates, and basic additives and halide abstractors are not required for high activity in transfer hydrogenation. Control experiments and a mercury poisoning experiment support a homogeneous catalyzed pathway. Overall, the fastest reactions are observed using electron-poor substrates and precatalysts bearing electron-rich ligands.
Mechanistic insights into ring-opening and decarboxylation of 2-pyrones in liquid water and tetrahydrofuran
Chia, Mei,Haider, M. Ali,Pollock, Gerald,Kraus, George A.,Neurock, Matthew,Dumesic, James A.
, p. 5699 - 5708 (2013/05/21)
2-Pyrones, such as triacetic acid lactone, are a promising class of biorenewable platform chemicals that provide access to an array of chemical products and intermediates. We illustrate through the combination of results from experimental studies and first-principle density functional theory calculations that key structural features dictate the mechanisms underlying ring-opening and decarboxylation of 2-pyrones, including the degree of ring saturation, the presence of C=C bonds at the C4=C5 or C5=C6 positions within the ring, as well as the presence of a β-keto group at the C4 position. Our results demonstrate that 2-pyrones undergo a range of reactions unique to their structure, such as retro-Diels-Alder reactions and nucleophilic addition of water. In addition, the reactivity of 2-pyrones and the final products formed is shown to depend on the solvent used and the acidity of the reaction environment. The mechanistic insights obtained here provide guidance for the selective conversion of 2-pyrones to targeted chemicals.
