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Budiman YP, Putra MH, Ramadhan MR, Hannifah R, Luz C, Ghafara IZ, Rustaman R, Ernawati EE, Mayanti T, Groß A, Radius U, Marder TB. Pd-Catalyzed Oxidative C-H Arylation of (Poly)fluoroarenes with Aryl Pinacol Boronates and Experimental and Theoretical Studies of its Reaction Mechanism. Chem Asian J 2024; 19:e202400094. [PMID: 38412058 DOI: 10.1002/asia.202400094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 02/27/2024] [Accepted: 02/27/2024] [Indexed: 02/29/2024]
Abstract
We report the synergistic combination of Pd(OAc)2 and Ag2O for the oxidative C-H arylation of (poly)fluoroarenes with aryl pinacol boronates (Ar-Bpin) in DMF as the solvent. This procedure can be conducted easily in air, and without using additional ligands, to afford the fluorinated unsymmetrical biaryl products in up to 98 % yield. Experimental studies suggest that the formation of [PdL2(C6F5)2] in DMF as coordinating solvent does not take place under the reaction conditions as it is stable to reductive elimination and thus would deactivate the catalyst. Thus, the intermediate [Pd(DMF)2(ArF)(Ar)] must be formed selectively to give desired arylation products. DFT calculations predict a low barrier (5.87 kcal/mol) for the concerted metalation deprotonation (CMD) process between C6F5H and the Pd(II) species formed after transmetalation between the Pd(II)X2 complex and aryl-Bpin which forms a Pd-Arrich species. Thus a Pd(Arrich)(Arpoor) complex is generated selectively which undergoes reductive elimination to generate the unsymmetrical biaryl product.
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Affiliation(s)
- Yudha P Budiman
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, 45363, Sumedang, Indonesia
| | | | - Muhammad R Ramadhan
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, 45363, Sumedang, Indonesia
| | - Raiza Hannifah
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, 45363, Sumedang, Indonesia
| | - Christian Luz
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ilham Z Ghafara
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, 45363, Sumedang, Indonesia
| | - Rustaman Rustaman
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, 45363, Sumedang, Indonesia
| | - Engela E Ernawati
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, 45363, Sumedang, Indonesia
| | - Tri Mayanti
- Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, 45363, Sumedang, Indonesia
| | - Axel Groß
- Institute of Theoretical Chemistry, Ulm University, 89081, Ulm, Germany
- Helmholtz Institute Ulm (HIU), Electrochemical Energy Storage, 89069, Ulm, Germany
| | - Udo Radius
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Todd B Marder
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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Ramadhan MR, Schlecht E, Dickhoefer U, Mahgoub O, Joergensen RG. Feed digestibility, digesta passage and faecal microbial biomass in desert-adapted goats exposed to mild water restriction. J Anim Physiol Anim Nutr (Berl) 2021; 106:721-732. [PMID: 34278606 DOI: 10.1111/jpn.13597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 04/23/2021] [Accepted: 06/08/2021] [Indexed: 11/30/2022]
Abstract
In arid and semi-arid environments, extensively managed ruminants regularly experience drinking water shortage, especially in the dry season. The present study therefore investigated the effects of mild drinking water restriction on feed intake, feed digestibility, solid digesta passage and composition of faeces including faecal microbial biomass. A feeding trial was conducted in Oman, during the dry summer months. Nine adult male Batinah goats were subjected to three watering regimes in a 3 × 3 Latin Square design. Treatments were (1) water offered ad libitum (100%, W100); (2) water restricted to 85% ad libitum consumption (W85); and (3) water restricted to 70% ad libitum consumption (W70). Animals were offered Rhodes grass hay and whole barley grains (1:1 ratio) at 1.3 times maintenance energy requirements. Each of the three experimental periods comprised 16 days of adaptation and 8 days of measurements. During the latter, feed offered and refused as well as faeces were sampled and quantified. Gastrointestinal digesta passage was determined using ytterbium-labelled Rhodes grass hay. Ergosterol and amino sugars were used as markers for faecal microbial biomass, that is the sum of fungi and bacteria. Water restriction had no effect on feed intake and digesta passage. However, feed dry matter, organic matter and fibre digestibility increased (p < 0.05) in W70 compared with W85, and the excreted amount of faecal dry matter, organic matter, nitrogen and neutral detergent fibre decreased (p < 0.05) in W70 compared with W85. Even though water restriction did not affect total faecal microbial biomass carbon (C) concentration, that of fungal biomass C increased (p < 0.05) in W70 compared with W85. Therefore, mild water restriction seems unproblematic from a physiological and nutrient utilization perspective as it increases feed digestibility without compromising feed intake.
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Affiliation(s)
- M R Ramadhan
- Animal Husbandry in the Tropics and Subtropics, University of Kassel and Georg-August-Universität Göttingen, Witzenhausen, Germany
| | - E Schlecht
- Animal Husbandry in the Tropics and Subtropics, University of Kassel and Georg-August-Universität Göttingen, Witzenhausen, Germany
| | - U Dickhoefer
- Nutrition and Rangeland Management in the Tropics and Subtropics, Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg Institute), University of Hohenheim, Stuttgart, Germany
| | - O Mahgoub
- College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman
| | - R G Joergensen
- Soil Biology and Plant Nutrition, University of Kassel, Witzenhausen, Germany
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