Palladium-catalyzed aryloxy- and alkoxycarbonylation of aromatic iodides in γ-valerolactone as bio-based solvent
| Autor: | Imre Tóth, József M. Tukacs, Eszter Albert, László T. Mika, Bálint Marton |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
010405 organic chemistry Aryl Organic Chemistry Iodide 010402 general chemistry Rate-determining step 01 natural sciences Biochemistry 0104 chemical sciences Catalysis Inorganic Chemistry Solvent chemistry.chemical_compound chemistry Nucleophile Materials Chemistry Alkoxy group Organic chemistry Physical and Theoretical Chemistry Triethylamine |
| Zdroj: | Journal of Organometallic Chemistry. 923:121407 |
| ISSN: | 0022-328X |
| DOI: | 10.1016/j.jorganchem.2020.121407 |
| Popis: | Fossil-based solvents and triethylamine as a toxic and volatile base were successfully replaced with γ-valerolactone as a non-volatile solvent and K2CO3 as inorganic base in the alkoxy- and aryloxycarbonylation of aryl iodides using phosphine-free Pd catalyst systems. By this, the traditional systems were not simply replaced but also significantly improved. In the study, the effects of different reaction parameters, i.e. the use of several other solvents, the temperature, the carbon monoxide pressure, the base and the catalyst concentrations, were evaluated in details on the efficiency of the carbonylations. To gather some information on the mechanism of these reactions, the effects of the electronic parameters (σ) of various aromatic substituents of the aryl iodides as well as the influence of para-substitution of phenol were investigated on the activity. For a comparison, the aryl-substituted aryl iodides were also reacted with methanol and aryl iodide was also alkoxycarbonylated using several different lower alcohols. From the observed correlations between the electronic parameters of the aromatic substituents and the rates, it appears that the rate determining step is the oxidative addition of Ar–I to Pd0, provided that sufficient amounts of nucleophiles are present for the ester formation. If this is not the case, the rate of nucleophile attack might determine the overall rate. |
| Databáze: | OpenAIRE |
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