- CO2-Catalyzed oxidation of benzylic and allylic alcohols with DMSO
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CO2-catalyzed transition-metal-free oxidation of alcohols has been achieved. Earlier, several methodologies have been explored for alcohol oxidations based on transition-metal catalysts. However, owing to the cheaper price, easy separation and nontoxicity, transition-metal-free systems are in high demand to the pharmaceutical industries. For this reason, various primary and secondary alcohols have been selectively oxidized to the corresponding carbonyl compounds using CO2 as a catalyst in the presence of different functional groups such as nitrile, nitro, aldehyde, ester, halogen, ether, and so on. At the end, transition-metal-free syntheses of pharmaceuticals have also been achieved. Finally, the role of CO2 has been investigated in detail, and the mechanism is proposed on the basis of experiments and DFT calculations.
- Riemer, Daniel,Mandaviya, Bhavdip,Schilling, Waldemar,G?tz, Anne Charlotte,Kühl, Torben,Finger, Markus,Das, Shoubhik
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p. 3030 - 3034
(2018/04/14)
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- The cascade synthesis of α,β-unsaturated ketones via oxidative C-C coupling of ketones and primary alcohols over a ceria catalyst
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We herein report the oxidative C-C coupling of ketones and primary alcohols to produce α,β-unsaturated ketones in the absence of base additives. This cascade synthetic reaction was conducted at 150 °C in 12 h using a heterogeneous CeO2 catalyst. The conversion of acetophenone reached 74% with 89% selectivity to chalcone. A correlation between the CeO2 crystal plane and catalytic performance is established as the catalytic activities decrease in the sequence of (110) > (111) > (100). Characterization using Raman spectroscopy, CO2 temperature-programmed desorption (CO2-TPD), and in situ active site-capping tests has shown that the unusual catalysis of the CeO2 catalyst is attributed to the coexistence of basic and redox active sites. These sites synergistically catalyze the oxidation of alcohols to aldehydes and the aldol condensation to ketones. Moreover, the CeO2 catalyst can be reused several times after calcination to remove the surface-adsorbed substances.
- Zhang, Zhixin,Wang, Yehong,Wang, Min,Lu, Jianmin,Zhang, Chaofeng,Li, Lihua,Jiang, Jingyang,Wang, Feng
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p. 1693 - 1700
(2016/04/05)
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- Oxygen as single oxidant for two steps: Base-free one-pot Pd(ii)-catalyzed alcohol oxidation & arylation to halogen-intact β-aryl α,β-enones
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Using oxygen as the sole oxidant for two steps, we developed a new method to synthesize β-aryl α,β-enones by fine-tuning the Pd(ii)-catalyzed oxidation of allyl alcohol to subsequent arylation with arylboronic acids, arylboronic ester and aryltrifluoroborate salt. This one-pot green method does not require copper salt, base, and intermediate isolation. Halogen-bearing chalcones, dibenzylideneacetones and arylalkyl enones were synthesized in good yields. This journal is
- Vellakkaran, Mari,Andappan, Murugaiah M. S.,Nagaiah, Kommu
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p. 45490 - 45494
(2014/12/10)
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- Lewis Acid - Mediated Addition of Lithiated Alkyl Phenyl Sulphones and Oxiranes. A Method for Synthesis of α,β-Unsaturated Ketones
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Efficiency of the reaction of lithiated alkyl aryl sulphones (1-4) with oxiranes (5, 6) is increased by the presence of BF3 or CeCl3.The respective adducts (7-14) were transformed into α,β-unsaturated ketones (15-22) with high yields.
- Marczak, S.,Wicha, J.
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p. 1511 - 1520
(2007/10/02)
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