- Cyclization of aryl 3-aryl propynoates into 4-arylcoumarins catalyzed by cyclometalated Platinum(II) complexes
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Cyclometalated (ppy)PtII complexes (ppy = 2-phenylpyridinato-C2,N) catalyze the intramolecular cyclization of aryl propynoates to form coumarins and benzocoumarins. The complex [(ppy)PtCl(MeCN)] (5 mol %) was the most active and effi
- Zaitceva, Olesia,Bénéteau, Valérie,Ryabukhin, Dmitry S.,Eliseev, Ivan I.,Kinzhalov, Mikhal A.,Louis, Benoit,Vasilyev, Aleksander V.,Pale, Patrick
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- Nanocatalosomes as Plasmonic Bilayer Shells with Interlayer Catalytic Nanospaces for Solar-Light-Induced Reactions
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Interest and challenges remain in designing and synthesizing catalysts with nature-like complexity at few-nm scale to harness unprecedented functionalities by using sustainable solar light. We introduce “nanocatalosomes”—a bio-inspired bilayer-vesicular design of nanoreactor with metallic bilayer shell-in-shell structure, having numerous controllable confined cavities within few-nm interlayer space, customizable with different noble metals. The intershell-confined plasmonically coupled hot-nanospaces within the few-nm cavities play a pivotal role in harnessing catalytic effects for various organic transformations, as demonstrated by “acceptorless dehydrogenation”, “Suzuki–Miyaura cross-coupling” and “alkynyl annulation” affording clean conversions and turnover frequencies (TOFs) at least one order of magnitude higher than state-of-the-art Au-nanorod-based plasmonic catalysts. This work paves the way towards next-generation nanoreactors for chemical transformations with solar energy.
- Cho, Yoon-Kyoung,Dubbu, Sateesh,Kim, Inki,Koo, Jung Hun,Kumar, Amit,Kumar, Sumit,Kumari, Nitee,Kwon, Taewan,Lee, In Su,Lim, Jongwon,Rho, Junsuk
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supporting information
p. 9460 - 9469
(2020/05/04)
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- Zeolite-promoted Synthesis of Coumarins and Thiocoumarins
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Acidic zeolites, especially faujasites, efficiently promote the intramolecular cyclization of aryl propynoates and propynethioates, which produces coumarins and thiocoumarins, usually in high yields. Comparison with homogeneous Lewis or Br?nsted acids and
- Zaitceva, Olesia,Bénéteau, Valérie,Ryabukhin, Dmitry S.,Louis, Benoit,Vasilyev, Aleksander V.,Pale, Patrick
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p. 326 - 333
(2019/11/13)
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- Palladium-Acid Co-Catalyzed Cleavage of Alkynoates to Construct Dibenzo[c,h]xanthene Derivatives
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A novel palladium-acid co-catalyzed C(sp)?C(sp2) cleavage of alkynoates for the construction of dibenzo[c,h]xanthene derivatives is reported. A catalytic amount of triflic acid (TfOH) afforded an efficient transformation into the final product. Furthermore, a reduction process of alkynoates was observed during the formation of dibenzo[c,h]xanthene, preliminary mechanistic studies indicated that the protonation of the new-formed methyl group in dibenzo[c,h]xanthene mainly came from water. (Figure presented.).
- Tang, Bo-Cheng,Wang, Miao,Ma, Jin-Tian,Wang, Zi-Xuan,Wu, Yan-Dong,Wu, An-Xin
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supporting information
p. 4023 - 4028
(2018/09/21)
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- Platinum-Catalyzed Desaturation of Lactams, Ketones, and Lactones
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The development of a general platinum-catalyzed desaturation of N-protected lactams, ketones, and lactones to their conjugated α,β-unsaturated counterparts is reported. The reaction operates under mildly acidic conditions at room temperature or 50 °C. It is scalable and tolerates a wide range of functional groups. The complementary reactivity to the palladium-catalyzed desaturation is demonstrated in the efficient conversion of iodide, bromide, and sulfur-containing substrates.
- Chen, Ming,Rago, Alexander J.,Dong, Guangbin
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supporting information
p. 16205 - 16209
(2018/11/23)
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- Rhodium(I)-Catalyzed Decarbonylative Aerobic Oxidation of Cyclic α-Diketones: A Regioselective Single Carbon Extrusion Strategy
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A rhodium-catalyzed decarbonylative aerobic oxidation of cyclic α-diketones has been developed for the first time, where the regioselective formations of α-pyrones and isocoumarins have been achieved. The current decarbonylative aerobic oxidation pathway proceeds via the C-C bond cleavage followed by a C-O bond formation, representing a biomimetic oxidation approach to unsaturated six-membered cyclic lactones. The unique ability of rhodium catalysts to induce the decarbonylative aerobic oxidation opens up a new synthetic toolbox that utilizes the "regioselective single carbon" extrusion strategy.
- Golime, Gangadhararao,Kim, Hun Young,Oh, Kyungsoo
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supporting information
p. 942 - 945
(2018/02/22)
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- Vanadium(III) chloride as an effective catalyst for the Pechmann reaction
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Good yields of substituted coumarins were obtained by a synthetic method involving the Pechmann reaction using vanadium(III)chloride (VCl3) reagent to effect this condensation under solvent-free conditions. 2006 Springer Science+Business Media, Inc.
- Sunil Kumar,Kumar,Srinivasulu,Rajitha,Thirupathi Reddy,Narsimha Reddy,Udupi
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p. 172 - 175
(2007/10/03)
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- Selectfluor: A simple and efficient catalyst for the synthesis of substituted coumarins under solvent-free conditions
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Selectfluor is used as an alternative catalyst to conventional catalysts for the synthesis of substituted coumarins via Pechmann condensation of phenols with β-ketoesters under solvent-free conditions at 120 °C. This method of synthesis is simple, cost-effective, requires short reaction time, solvent-free and gives good yields.
- Kumar, B. Sunil,Reddy, Y. Thirupathi,Reddy, P. Narsimha,Kumar,Rajitha
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p. 477 - 479
(2007/10/03)
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- Nickel-catalyzed highly regio- and stereoselective cyclization of oxanorbornenes with alkyl propiolates: A novel method for the synthesis of benzocoumarin derivatives
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7-Oxabenzonorbornadienes bearing various substituents react with propiolates in the presence of [NiBr2(dppe)] (dppe = bis(diphenylphosphanyl)ethane) as a catalyst precursor and zinc powder to give benzocoumarin derivatives [Eq. (1)]. The one-pot reactions proceed at 80°C in acetonitrile, and the products are obtained in good yields with high regio- and stereoselectivity.
- Rayabarapu, Dinesh K.,Sambaiah, Thota,Cheng, Chien-Hong
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p. 1286 - 1288
(2007/10/03)
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